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Building the Tom Henry RS

Part One: Easy Stuff First

Since Camaro's 1967 debut, a six-cylinder engine ('67-'79, I-6; '80-'02 and '10-up V6) has been either standard or, for four years in the early-’80s when General Motors made the awful mistake of an inline-four for a base engine, a midlevel option.

For the Camaro's first ten years, V8s outsold sixes by a considerable margin, but in 1977, with our country in the throes of an agonizing gasoline shortage, V6s sold on par with V8s. From then on, until production temporarily ceased after model year 2002 (MY02), six-cylinder market penetration averaged 50.4% and, for MY93-02, V6es sold 62.4%. Bottom line, there’s a ton of sixes out there, especially in fourth generation Camaros and that trend is sure to continue with the fifth generation,  2010-up cars.

One reason V6es sold well towards the end of the 4th Gen era was the 200-hp, 3.8-liter engine introduced in halfway through 1995. Called “3800 Series 2”, it’s the unblown version of the supercharged motor used up to MY05 in the Impala and Monte Carlo SSes. By mid-'90s standards, for buyers looking for a sporty coupe but for whom performance was a consideration but not the most important one, this offered a more affordable alternative to the V8-powered Z28s and SSes.

Back in late-'05 and early-'06, when gas prices went bonkers, visitors to our parent company, Tom Henry Racing (THR) about V6es. Aftermarket companies tell us demand for V6 performance products has grown indicating interest in hot-rodding those cars. There are even web sites devoted to V6 Camaros at www.forum.camarov6.com and www.3800pro.com/forum/.

Here's our project car. It'll take us about year but it will end-up as the Tom Henry RS and will use a few general ideas we hope to see in the '09 base Camaro. Image: CHpg staff.

We decided to jump on the bandwagon, acquire a 2001 Camaro V6, 5-speed and try some mods. We're calling the car a "Tom Henry RS", in honor of the famed V8-powered Tom Henry SS "tuner" Camaros of  '01 and '02. Since we're starting this project in the dead of winter, we've farmed the job out to THR's, West Coast development "laboratory" near Los Angeles.

Our goal is more exciting street performance, not building a drag race car. In addition this project is a little bit of "what-if". We want to modify the engine to about the 300-hp level to match the performance of a 2010 Camaro. Additionally, we're going to modify the suspension of this 4th Gen V6 and see what happens.

Our engine mods will pass a state exhaust emissions test and won't degrade low-end torque. Our suspension enhancements will improve handling but will still have the car riding reasonably nice enough for commuting over the rough surfaces of freeway/expressway systems in cities with the worst roads in the country, such as Philadelphia, Detroit and Los Angeles.

Before we start working, let's talk about service data because information is power–power over your Camaro if you work on it yourself. Unless you’re an experienced Camaro technician, you need a factory service manual (FSM) from Helm, Inc., publisher of GM all service data. Our 2001 Chevrolet Camaro Service Manual was indispensable in preparing this series.

Information is power. The best service information on any Camaro comes in the factory service manual--actually, in this case, three manuals. Image: CHpg staff

          A downside of the factory manual is cost. Some of the stuff we are going to do to the Tom Henry RS is discussed in the less-expensive, 1993-2002 Camaro Haynes Repair Manual. While the Haynes omits some front suspension information, suggests some questionable tool choices, and erroneously states you can’t work on the brakes without a scan tester; it's an acceptable reference for those on a tight budget doing regular maintenance or basic repairs. On the other hand, if you're getting into engine controls diagnosis or heavy mod'ing, buy the FSM.

What about parts? Most of the GM and aftermarket parts we're going to use during the next 12-months or so can be sourced from Tom Henry Racing, the performance parts sales division of Tom Henry Chevrolet. In the case of the few parts which can't be purchased from THR, we'll tell you where to get them.

The staff of Tom Henry Racing's parts operations, headed by Parts Manager, Stan Lorence, stands ready to assist any Camaro Homepage visitor in finding Camaro parts. Additionally, the people at Tom Henry Racing's Service Department, headed by Manager, Cory Henderson, can install many of the modifications discussed in this series.

First Mods

After wheels and tires, perhaps the most popular aftermarket modification performed by Camaro fans is the addition of an aftermarket exhaust system. Flowmaster’s American Thunder system for ‘98-’02 Camaros with 3800 V6es (PN 17358) has larger, 2.5-in. aluminized pipe, an 80-series muffler and stainless steel tips, all typical Flowmaster features. It's unique part is a resonator, cleverly-packaged beneath the passenger-side rear seat. Flowmaster says that certain frequencies of V6 noise are difficult to attenuate and this resonator facilitates that. One Saturday, we got the car up on jack stands and installed the American Thunder system using hand tools. We demanded increased performance, improved sound and better appearance. Flowmaster’s cat-back got us all three.

When we tried to get the stock exhaust off, we found the slip-joint behind the cat rusted tight. An overnight treatment with Sili-Kroil aerosol, one of the best penetrants on the market sold by Eastwood Company, and some additional blasts with Sili-Kroil as we beat the old exhaust off with a hammer, finally brought success. It's amazing the restriction in this area of the system where there are four reductions in pipe size. The Flowmaster exhaust eliminates the final step. Modifications we'll do later in the project will eliminate the third step. Image: CHpg staff.

The Flowmaster exhaust for ’98-’02, V6s. Similar systems are available for ’95-’97s 3.8s (PN 17357). It uses stock exhaust hangers, comes with hardware and has large, stainless steel tips. The sound is the seductive, deep tone for which Flowmasters are famous. Image: CHpg staff.

          Chassis dynamometer testing will be a key part of this project series. All of our chassis dyno work will be done by the Westech Performance Group in Mira Loma, California. Westech's owner, Rick Stoner is a long time Chevrolet enthusiast and owns a number of Chevy hot rods and classic Corvettes. Westech's key specialties are dynamometer testing, both engine and chassis, and custom engine building. Westech’s SuperFlow SF840 chassis dynamometer is a state-of-art piece of equipment which can be run in either the "brake dyno" or "inertia dyno" modes. For simple performance validation, Dynamometer Test Technician Ernie Mena typically runs the SF840 as an inertia dyno.

This is Ernie Mena setting-up a wide-band O2 sensor prior to one of the many tests we ran at Westech Performance Group in the process of modifying this car. Westech uses a unique, vacuum assisted O2S sensor which quickens the system's response. Image: CHpg staff.

This is the Vericom VC3000 which replaced the veteran, VC2000 a couple of years ago. It has typical Vericom features: two-axis accelerometer core, 400Hz sampling rate, and ability to upload data to a PC. New with the 3000 are: larger 128x64 LCD screen, ability to recall up to 256 tests from memory, better keyboard, better mounting system, USB port and–we saved the best for last–with the DAQ model, ability to record OBD2 data via the car's diagnostic link connector (DLC) as well as from up to six accessory sensors. In our experience, the Vericom VC3000's larger display and improved keyboard make it nicer to use and the built in bubble levels are a handy feature. Image: Vericom Computers.

          Westech's Superflow showed our V6 with the Flowmaster American Thunder exhaust system gained a hair over 11, horsepower (SAE-corrected) at the rear wheels and road test numbers backed that up. Using a Vericom VC3000 Performance Computer, an on-board vehicle dynamics tester, we saw 0-to-60 time decrease from 7.83 to 7.44-sec. and quarter mile stats going from 16.15-sec./89.14-mph to 15.87/90.69.

          Eleven horsepower and nearly two tenths and a mile-and-a-half an hour in the quarter is an outstanding improvement for just an exhaust change on a car which, in stock trim, made only 162-hp (SAE) at the wheels. Clearly, the O.E. exhaust is restrictive. In addition, it was too quiet, sounded funky and had ugly tail pipes. The American Thunder system gives that deep-toned, trademark Flowmaster sound and its stainless outlets look a lot better. The Aussies at Holden, who are doing most of the vehicle development of the 2010 Camaro, need to listen to our project car so they won't make the  same mistake made by GM on the 4th Gen car and put a wimpy exhaust on V6es.

          At Tom Henry Racing we put lubricants from the Red Line Synthetic Oil Corporation in a lot of customers' modified, street high-performance Chevrolets. From the Cobalt SS Supercharged to the Impala SS and from the Camaro to the Corvette Z06, just about any hot rod Chevy can benefit from Red Line's premium synthetic products.

          In this project car, we used Red Line 10W30 Engine Oil, Red Line Power Steering Fluid in the power rack-and-pinion steering system, a 50/50 mix of Red Line D4 ATF and Red Line MTL in the car's TREMEC T-5, five-speed transmission and Red Line Heavy Shockproof Gear Lubricant in the rear axle. The gain was slight, 1.5hp (SAE) at the wheels, so the chief advantage of Red Line products is their enhanced thermal stability and the better durability of powertrain components which comes from that. There’s also the possibility of extended engine oil drain intervals, if we choose.

We began our Red Line Synthetic conversion with 10W30 Engine Oil, and Power Steering Fluid. Image: GHpg staff.

Going Green is easy. Pop open the filter housing, remove the dirty, stock filter and slip in the Green. Image: CHpg staff.

          We wanted an oiled cotton air filter so we added a “Green Filter” (PN 2021) we got from THR. While many filters have cotton media, a Green uses two layers of woven cotton which are thinner, stronger and hold filter oil better than the gauze used by K&N and others. The Green Filter people say that, because it’s woven, the thinner material still traps particles as small as 5 microns. More interesting is what they claim about filters with injection-molded edges. During molding, rubber can leak onto the filter which reduces its area. Since a Green’s edges aren’t injection molded; that can’t happen. When we compared a Green to an injection molded K&N Filter, sure enough; we noticed that difference.

The stock, ACDelco 41-921 (top right) and the Denso IT-20. They are different designs--the ACD plug is platinum-tipped, the Denso uses an iridium tip and is, also, a colder heat range, better suited to an engine which runs hard. Image: CHpg staff.

The Denso "Iridium Power" IT-20 has a very small, Iridium center electrode along with a cut-back and tapered, ground electrode. Both these features allow the air-fuel mix in the combustion chamber increased exposure to the spark. As a tip material, Iridium has as good or better durability than platinum, but lower resistance. That lower resistance can make a more powerful spark available at the plug. Image: CHpg staff.

Dyno runs, quarter mile testing and aggressive street driving made colder spark plugs desirable, so we installed Denso IT-20 Iridium Power plugs which are sold by THR. The IT-20 is one heat range colder and its iridium tip is more durable but has less resistance than the stock platinum, AC Delco plugs that were in the engine when we started. The Densos' small, 0.4-mm center electrode and tapered ground electrode give the spark maximum exposure to the incoming, air-fuel charge. We should add that even General Motors must see merit in the Denso spark plug design because after about 2004, some Chevrolets have Densos from the factory.


 MSD Super Conductors are the same length as the stock wires. The 8.5-mm. MSDs fit the stock wire looms. Red wire and gray boots add a little color to an otherwise colorless engine. Image: CHpg staff

The 8.5mm Super Conductor Spark Plug Wire has many design features intended to meet the reliability/durability needs of NASCAR NEXTEL Cup race engines. Image: Autotronic Controls Corp

          We put MSD’s Super Conductor plug wires (PN 32089) on our modified 3800. Their design came out of stock car and road racing several years ago. They have low resistance but radio frequency interference (RFI) suppression equal that of stock wires. The Super Conductor core is Kevlar around which is a tightly-wound, copper wire. A foot this stuff has about 40-feet of coiled wire which acts like an RF choke and suppresses RFI. The outer sleeve is heat, abrasion and tear resistant. Add super grippy connectors and durable, heat-resistant silicone boots, the choice of black or red  and you’ve got a great plug wire. Super Conductors’ lower resistance increases the performance margin of our ignition system, which could come in handy later, and the high suppression keeps the Tom Henry RS's Monsoon sound system noise-free.

          We stuck a Stant 180° thermostat (PN 45848) in place of the stock 195° unit. Running the cooling system at 180° may reduce the engine’s tendency to detonate and will improve durability of underhood rubber and plastic. Next we swapped the O.E. drive belt for a Goodyear Gatorback Poly-V belt (PN 4060940). Its diamond-checked back allows the Gatorback to run up to 15° cooler, extending belt life. Lastly, we added a bottle of Red Line WaterWetter to the coolant. WatterWetter can improve cooling performance when the engine is run hard.

 The Goodyear Gatorback belt, by virtue of its diamond-checked backing, generates less heat as it flexes around the pulleys. This lengthens belt life. The Stant 180 ‘stat is an easy swap on a 3.8L V6. CHpg staff.

 The Goodyear Eagle F1 GS-D3, known for its “flying-V” tread, is an outstanding performer on wet roads and one of the better, all-round, ultraperformance radials on the market . CHpg staff.

Speaking of Goodyear, the last big American tire company, its Eagle F1 GS-D3 is a killer, all-weather, ultraperformance radial tire. It has good dry traction and, by virtue of its distinctive tread pattern which aggressively channels water away from the tread, great performance on wet roads. It also has excellent tread life and low noise characteristics. Lastly, it has Goodyear’s neat “Rim-Guard” feature which lowers the chance of wheel damage if we scrape a curb. We swapped the stock, T-rated, 235/55R16s for a GS-D3s in P245/50ZR16. As these Z28-sized tires fit on our stock 16x8-in. wheels, the switch was simple. We ordered the GS-D3s from Tucker Tire in Covina California, then had Tucker’s professionals mount and balance them.

Now, we needed a little DIY computer reprogramming. We used a Hypertech Power Programmer (PN 30009) to lower our engine control module's (ECM) fan-on temperatures to match the 180° thermostat, to alter the vehicle speed limiter above what was stock with T-rated tires and optimize the speedometer calibration for the slightly-smaller-diameter, Goodyear F1 GS-D3s.

Working a Little Harder

               The first mods where easy but now, we’ll earn our pay. Under the back of this Camaro was that gleaming Flowmaster exhaust but a nasty-looking rear end. We didn’t want to take the rear end apart to have the housing grit blasted before we could paint it because, then we’d have to set-up the gears. Not!

          The Eastwood Company has a paint called “Rust Encapsulator” which spokesman, John Sloane, told us, “...is a slow-cure enamel, fortified with a fine glass-flake amendment which seals the surface.”

          Seal the surface and rusting virtually stops. “R.E.” can be used alone or as a primer, over which you can apply just about any paint. It’s intended for spray application after thinning with 20% lacquer thinner, but can be brushed on, if you add 10% retarder.

 ECM calibration was a task with which we became very familiar on this project. Our first attempt, was pretty basic. We used a Hypertech Power Programmer to lower the fan-on temps and to change the ECM’s tire size programming to work with the 245/50ZR16 Goodyears. As time went on, as you'll read in future installments of this project, calibration became our bane. CHpg staff.

Our initial experience with Rust Encapsulator was brushing it on but buying  the aerosol version is a better idea. Either way, RE saved a lot of work. CHpg staff.

          We plugged the brake hose connection on the chassis, then got the Camaro’s axle out, stripped-off the brakes, capped-off the caliper hoses, masked its vent and ABS sensor connection.

          Some aftermarket service data, like the Haynes Repair Manual, claims you shouldn’t remove brake components because that lets air in the system then a scan tester is required to bled it. That’s bunk. It is true that, in the unlikely situation that you loose enough brake fluid such that the ABS brake valve drains, you need the scan tester to bleed the ABS; however, when you remove the rear axle or the front calipers, immediately plug the connections on the chassis and the brake hoses. Once you reconnect the brake plumbing, bleed the brakes manually to get the small amount of air out of the lines and hoses and you're set.

Since we had both the Flowmaster exhaust off and the rear axle out, not only did we use the Karcher 2650HH to wash the rear axle but we blasted the whole underneath of the back of the car. Image: CHpg staff.

           Next we cleaned the rear axle with warm water and Simple Green using a Karcher 2650HH Pressure Washer we bought at Costco. We blew the axle dry with shop air, masked-off the brake hoses and the parking brake levers then painted it with Rust Encapsulator (PN16040Z). After overnight drying, we shot it with Eastwood Extreme Chassis Black (PN11175Z). After a second overnight dry we reinstalled the axle, reassembled the brakes then bled the rear calipers.

“Chassis Black” has been around for years but, recently, Eastwood revised its formula, adding to the product’s already good durability. We used new, “Extreme Chassis Black” on the Camaro’s rear axle. How ‘bout that snazzy spray gizmo on the can? We found that at Ace Hardware. Image: CHpg staff.

Getting the axle in-and-out of a 4th-gen is easy and moving it is a snap with a floor jack. A second set of jack-stands supported the axle while we hung the new suspension. Image: CHpg staff.

          Global West Suspension Systems, an engineering-driven manufacturer of high-performance suspension pieces for Camaros and other Chevys, has a brand called “Quiet Ride”. These products combine polyurethane or rubber bushings with spherical bearings for a decrease in deflection but only a modest increase in harshness. Quiet Ride parts are for high-performance street use, not racing, and are available from Tom Henry Racing.

The GW rear arms each have a rubber bushing and a spherical bearing. Rubber goes in the body pickup point and the bearing bolts to the axle. Image: CHpg staff.

Here are most of the pieces we used in the rear. The Bilsteins have heavy-duty valving which improve the handling of any 4th-gen Camaro. Image: CHpg staff.

Once the control arms are in place, set the isolator atop the spring, then raise the spring, such that its top goes into the spring seat, then push it onto the rear axle.  Image: CHpg staff.

Between the much stiffer lower control arms and the aggressively-valved Bilstein shocks, the rear suspension is going to deflect less and better damped. Access the shocks’ top nuts through the interior. On the bulkhead behind the rear seat are two carpeted access flaps. Fold them back, pull out the sponge insulators and there are the nuts. Once the shocks’ lower bolts are tight, you can take the rear end off the jacks. Image: CHpg staff.

We bolted-on Quiet Ride tubular steel, rear control arms (PN TBC14) which fit ‘82-’02 Camaros and offer an increase in rigidity over the stamped-steel stockers. GW arms use a Moog, rubber bushing in the body end and a spherical bearing on the axle end. These arms can be installed in an hour.

Next, we ordered Eibach Springs and Bilstein high-pressure, gas shocks. The rear Eibachs are a stiffer, progressive rate design, dual-rated at 75 and 135 pounds-per-inch. They lower the car about 1.5-in. and are part of the “Pro Kit” (PN 3870.240) for V6 Camaros. The Bilsteins' (PN B46-1914) stiffer damping is an excellent match for our spring rates and ride height. We added a 19-mm, Z28 rear stabilizer bar. We used the production Camaro mounts and end links but installed Global West polyurethane link bushings (PN 19-428).

 Side-by-side are the stock and Global West trackbars. The GW upgrade offers an increase in rigidity and is of value to any modified Camaro, be it an autocrosser or a drag racer. Image: CHpg staff.

One neat feature of the Global West Trackbar is that it's adjustable so the chassis can be centered on the rear suspension no matter what the ride height. You loosen the nuts then turn the hex section as necessary to center the chassis. Image: CHpg staff.

The rear stabilizer and Global West Trackbar are in place, so the rear is done, except for centering.  Image: CHpg staff.


We finished the rear with a Global West, Quiet Ride Trackbar (PN PHC3), an improvement over the flimsy, rubber-bushed stocker. Made of tubular steel with a poly bushing in one end and a bearing in the other, it’s a stiffer lateral link so suspension deflection during cornering is reduced. It’s adjustable for length, so the body can be centered, regardless of ride height. All these rear suspension parts came from Tom Henry Racing.

Aftermarket service manuals say to use a pickle fork and a hammer to separate ball joints and tie rod ends. Not! That's a lot of work and it renders good parts unusable. Use a ball-joint and tie-rod removal tool like this one--it's much easier on you and the parts. Image: CHpg staff.

          On to the front suspension. We pulled off the front brakes, popped the ball joints loose then removed the steering knuckles, the struts and the front control arms. Let's take a minute to expand upon the subject of polyurethane suspension parts. "Poly" is common in suspension upgrades, however, it's not appropriate in all situations. Urethane is more rigid than rubber so, on a car with ride travel typical of road cars, when a suspension nears compression and rebound limits, urethane can bind suspensions which have control arms which twist as well as move up-and-down. Examples are rear bushings in 4th-gen front lower arms or the bushings in the rear arms. On the street,  if you want reduced deflection, it’s better to use high-durometer-rubber bushings from the FE7 suspension. Some may know these as “1LE bushings”, though they were on cars other than 1LEs. These bushings noticeably decrease deflection, however, they won't bind the suspension on street cars nor are they overly harsh.

          We ordered stock, FE7 front lower bushings (PN 22145392 and 22156434) from the Tom Henry Racing. We, also, ordered Moog’s “enhanced design” lower ball joints (PN 6145T) which have pressed-in rather than folded-over bottom plates and come with grease fittings, both durability and performance upgrades. Moog is a supplier to NASCAR, so if they’re good enough for the Busch and Cup guys; they’re good enough for us.

          Both the bushings and the ball-joints have to be pressed-in. Since we were ordering the parts from THR, we shipped the arms to Tom Henry Chevrolet's Service Department and had them run next door and get the parts, install them and ship the arms back. Finally, we wet-abraded the lower arms using Standard Abrasives Medium BriteRite Pads with hot Simple Green and water. We dried them with shop air then, then shot them with Eastwood Extreme Chassis Black.

The Tom Henry Chevrolet Service Department uses an assembly of J-Tools in a hydraulic press to install and automatically set the position of bushings. Their positions in the front lower arm is critical to avoid interference between the arm and the crossmember when the suspension rebounds. You can install bushings using traditional methods, but you must set them at specific positions. Push the front bushing in from the rear until 3/16-1/4-in. is left exposed. Push the rear bushing in from the bottom, until 7/16-1/2-in. protrudes above the arm. Image: CHpg staff

When reinstalling control arms with rubber bushings, have the arms at ride height while tightening the bolts. Bushings don't rotate, they twist. Tighten the bolts with the suspension hanging and, when it returns to ride height; the bushings are constantly twisted. When the suspension nears full compression, they’ll really be twisted, which can damage the bushings. Also, with the rear bushing in the front lower arm of a 4th-gen car, if you tighten the bolt with the suspension hanging, the bushing may turn off-axis in the crossmember. If that happens, setting alignment is difficult, the misaligned bushing can cause increased harshness and the crossmember and bushing may be damaged.

We disassembled the front strut assemblies, scrapped the stock springs and shocks then installed the stock spring seats, 377 lb/in. front springs out of the Eibach Pro Kit and the stock upper spring mounts onto two Bilstein shocks (PN B46-1913).

While the procedure of using the garage floor or other flat surface as a "jig" while assembling the struts seems all-too-simple--it works very well. Image: CHpg staff.

The Tom Henry service department uses a high-dollar, J-tool jig in a hydraulic press to assemble 4th-gen front struts, equipment out-of-reach of most DIYs. You can use ordinary strut compressors if you orient the shock’s lower mounting bar and the upper strut mount in specific positions while tightening the shock absorber nut.

Your “jig” is your garage or shop floor. Each strut mount has two threaded studs and a rubber pin near its front edge. Once the struts are assembled with the springs compressed, the springs’ upper ends seated in the strut mounts and the shock absorber nuts loose, lay the struts with the front edge of each mount flat on the floor. Rotate the left shock so the end of its lower mounting bar is flat on the floor and (looking at the strut top) inclined down to the right (pointed outside the vehicle). Rotate the right shock so the end of its mounting bar is flat on the floor with (looking at the strut top) the crossbar inclined downwards to the left (pointed outside the vehicle). Now, tighten the shock nut and remove the spring compressors and you’re ready to stick your struts back on the car.

The Global West Del-A-Lum is really a bearing not a bushing. The blue aluminum shell is pressed into the control arm. The gold steel sleeve rides on the control arm shaft or bolt and is locked in place. The Delrin sleeve "floats" between the two. Layers of grease are between all the parts. Del-A-Lums are a better choice than polyurethane bushings because they never squeak, do not bind the suspension and have better durability. Image: Global West Suspension.

Next, we had the Tom Henry Service Department install Global West Del-A-Lum “bushings” in the car's stock uppper control arms. Del-A-Lums are not really bushings but Delrin/Aluminum composite suspension bearings. Swapping the stock rubber bushings for Global's parts eliminate deflection of the front upper arms under cornering loads which makes the car's handling more predictable and consistent. Since the Tom Henry RS is still primarily a street car, the Del-A-Lums in the uppers and the production 1LE rubber bushings we installed in the lower control arms make a great combination. The lower arms take virtually all the impact loads, so keeping rubber in those arms allows us to retain a modest level of compliance to keep impact harshness and noise at an acceptable level. Since we had the upper arms off, once the Del-A-Lums were in place we, also, added new, Moog heavy-duty ball joints (PN K6462) to the arms.

The OE bushing (left) and the Del-A-Lum. Obviously, the Del-A-Lum is a less compliant, but not quite as stiff as a solid metal bushing. The delrin-aluminum composite design with the parts separated by grease makes for outstanding durability. It's not uncommon to have Global West Del-A-Lum outlast the car it's on. Image: CHpg Staff.

The THRS's stock front upper control arms fitted with Global West parts and Moog ball joints. Image: CHpg Staff.

Like most suspension "bushings" the Del-A-Lums are best installed using a hydraulic press along with a small, temporary "spacer" to keep the arm from collapsing when the bushing shell is pressed into the arm. Image: CHpg Staff.

We assembled the arms and the control arm mounting brackets then stuck the refurbished lower arms, the Eibach/Bilstein struts, the mod'ed upper arms, the steering knuckles, a pair of Moog tie rod ends (PN ES3238RL) and all the brake hardware back on the car.

The upper arm, its mounting bracket and the strut are installed as a unit. Guide the strut mount studs though the shock tower, hold the lower control arm down then push the strut’s lower mount onto the arm. Image: CHpg staff.

We bolted the front brakes in place, bled them and we were done with the front, except for an alignment. Image: CHpg staff.

This is the SPX Kent-Moore tool which alignment shops should use when setting the camber and caster on the front of a 4th-gen Camaro. You can do the alignment without the tool, however you'll end up with the lower control arm bushings preloaded and that tends to decrease their reliability-durability. Image: CHpg staff.

          While we're on the subject of doing the job right, let's talk about tools. Marketed by SPX Kent-Moore, GMs supplier of service equipment, specialized tools (Techs at Tom Henry Chevrolet Service call them “J-Tools”) are sometimes needed. J-Tools for bushing installation and strut assembly are not necessary, however, the “Caster/Camber Adjusting Tool” (J-38658) is required. You can’t adjust camber without it because you end-up tightening the bushing bolts with the suspension hanging.

          Our front suspension upgrade ended with a stock Z28, 30-mm front stabilizer bar from and Global West polyurethane mounts (PN 19-1146) and links (PN 19-409) from THR.

          With suspension mods done for now, we bolted the Goodyear F1 GS-D3s back on and took the Tom Henry RS to Tucker Tire for front end alignment and to center the rear using the GW Track Bar’s adjustment.

Amanda Dakai, a Tucker Tire suspension technician, works the camber/caster gauge. Tucker Tire is one of  L.A.’s top suspension centers with four alignment racks running all day long. Yes, you need a reservation. Image: CHpg staff.

Just One More Thing

Installing higher-ratio rockers on a 3800 in a Camaro is fairly easy. You remove the ignition hardware, pull the valve covers then trade the stock rocker bolts, rockers, pushrods and support bar for the SLP parts. Image: CHpg staff.

            The final step in Part One of the Tom Henry RS project was to install a set of SLP Performance Parts, 1.8:1-ratio, rocker arms on the car's 3800 V6. These come in a kit that includes .300-in. longer pushrods and new GM rocker arm bolts. Longer pushrods are required because the SLP rocker's pushrod seat is 3/10th of an inch higher than stock and the new bolts are necessary because the O.E. units are "torque-to-yield" fasteners which cannot be reused.

Where as the stock rockers are investment-cast steel with a roller fulcrum, the SLPs are machined aluminum with roller fulcrum and tip. They are about half-an-ounce lighter. Image: CHpg staff.

While changing rockers on our 3800 Series II, we prelubed the  rockers with Red Line 10W30 oil and we dabbed some Red LIne Assembly Lube on the valve stem tips. Also, you must replace  the rocker bolts, if you stick with GM bolts. ARP makes a  reusable 3800 rocker bolt and later in the project, we'll  install a set.
 Image: CHpg staff.

We're almost ready to put the valve covers back on. We still need to squirt some Red LIne 10W30, into the top of each rocker, stick new Fel-Pro gaskets in the covers then  reinstall them. Then, we'll put the ignition hardware back on and go testing. Image: CHpg staff.


The stock rocker ratio is 1.6:1. Higher ratio rocker arms offer more valve lift and duration for a given lobe lift. The stock cam for an unblown 3800 has .256-in. lobe lift. With that cam, valve lift with stock rockers is .410" but with the SLP 1.8s, it's .460". Generally, more valve lift means more air into the engine and more power out.

Another difference between the SLP 1.8s and the stock rockers is 0.5-oz. less weight per rocker. In theory, a lighter rocker taking mass out of the valvetrain should improve the engine's ability to "RPM", however, right now, the engine in the Tom Henry RS peaks at 5000 rpm and we've still got the stock rev. limiter in the ECM calibration so even if the SLPs do offer an advantage at high rpm, at this point; we can't use it.

With the SLP rockers installed, we went back to the chassis dyno at Westech. In a series of six passes on their Superflow 840, three with stock rockers and three with the SLP 1.8s, the results were mixed. At 4900-5000 rpm we saw just a hair less than a 6-hp average increase, but below 3400 rpm, we saw as much as a 3.5-hp loss. This increase up high but a loss down low is typical of adding both lift and duration. Nevertheless, from 3700-up, there's a consistent increase so, in the real world, on the street or the drag strip, you might see a slight decrease in e.t.

Most of the time, you see chassis dyno information as curves. Superflow's software can do a lot of interesting number crunching. This graph offers a more visual representation of the improvement that we got with the SLP rockers. The blue baseline is the average of three passes on Westech's SF840 before the rockers. The red graph is the average power improvement below or above the baseline from three runs with the 1.8 rockers installed. We don't know why this representation style is used more often because we think it's a better way. Image: CHpg staff.

This particular 1.8 rocker is not available direct from SLP but is sold by LM Performance. The manufacturer of these rockers was Yella Terra, an Australian company which makes performance products for 3800 Series II V6es (down-under, they call it the "Ecotec 3800") and private-labeled them for SLP. Once LMPerformance sells out of the SLP 1.8s, V6 Camaro DIYs will be able to get to Yella Terra's "second-design" 3.8 rocker which is available in both 1.8:1 and 1.7:1 ratios. Later in this project we'll acquire a set of the Yella Terra 1.8s and test them but, for now, the SLPs work quite well.

We'll be back in about two months with the second installment of the Tom Henry RS built-up in which we'll really roll-up our sleeves and turn some wrenches. We'll start with cylinder head modifications.

Click here to read Tom Henry RS Project Part 2

All the GM parts and most of the aftermarket parts discussed in this article are available from Tom Henry Racing at www.tomhenryracing.com. The products not available from THR are listed below:

American Kleaner Mfg.
 (Karcher Pressure Washers)
Box 3900
Rancho Cucamonga  CA  91729

Eastwood Company
263 Shoemaker Rd.
Pottstown  PA  19464

Haynes Publications, Inc.
861 Lawrence Dr.
Newbury Park, CA  91320

Helm, Inc.
14310 Hamilton Ave.
Highland Park, MI 48203

LMPerformance, Inc.
PO Box 534
Destin, FL 32540-0534

SPX Kent-Moore
28635 Mound Road
Warren, Michigan  48092-3499

Valco Cincinnati
411 Circle Freeway Dr.
Cincinnati, Ohio 45246

Vericom Computers, Inc.
14320 James Road
Suite 200
Rogers, MN 55374 USA

Westech Performance Group
Unit C
11098 Venture Av.
Mira Loma  CA   91752


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