When the team stepped up to 28–inch–tall ET Drag slicks, the tires interfered with the wheelhouses,
so they were modified. The team cut a wedge–shaped section out of the urethane rear bumper cover (A)
and spliced the remaining pieces together (B). Since this placed all the gain in clearance at the rear
of the arch, the axle was repositioned ½ inch rearward to re–center the wheels.
Traction Upgrades
Traction became more of an issue, so the team bolted on some 28.5–inch ET Drags, which in
turn triggered a series of other modifications. The larger tires wouldn’t fit in the wheelwells, and
since the team didn’t relish cutting quarter–panels, the students recognized that the rear portion of
the wheels arches were actually formed by the rear bumper cover, which is easily replaced. The cover
was sectioned 1¾ inches for increased clearance, but taking this approach necessitated relocating the
axle rearward to re–center the wheels by drilling new control arm mounting holes in the axlehousing ½
inch forward of the stock location. Of course, this mandated a longer driveshaft, so they built a
3½ –inch steel tube with 1350 series U–joints and billet yokes. (Two custom aluminum driveshafts
had failed.) The 12–bolt was then fitted with 4.30:1 gears to offset the height of the taller tires.
To further enhance launches, the team changed the front mount of the Random Technologies
torque arm from a slip joint to a solid mount and replaced the factory dampers with AFCO double–adjustable
shocks. Finally, factory V–6 rear springs were installed to aid weight transfer.
With the power curve on an upswing, they installed a Kenny Thomas Racing Enterprises
12–bolt axle fitted with 4.10:1 gears and a McLeod 12–inch clutch assembly. Along with this hardware,
they posed M/T ET Street 26×11.5–inch slicks for maximum launch and were rewarded with a 12.28 at 112.05.
To complement the tire upgrade, the team installed 4.30:1 gears. The increase in traction prompted them
to alter the Random Technologies torque arm by changing its forward mount from a slip joint to a solid pivot.
John Harrison of Specialty Metal Craft handled the fabrication work. The stock torque arm mounts to a bracket
on the T–56 transmission case, as did the Random Tech design. Harrison altered the factory transmission
crossmember by adding a mount to accept the bushed eyelet he welded to the torque arm. The crossmember was
also reinforced to weather the extra loading from the torque arm.
Prototype Intake
Once the Camaro was able to use all of its power consistently, the team resumed the
search for more. One of the obstacles that hamstrings this equation is the stock LS1 intake manifold.
Until recently, the only one available was the plastic factory piece. The assumption was that this
material could not be ported, but the students quickly discovered that it could by using Devcon Plastic
Steel Putty to reshape the ports as needed. However, after spending considerable time re–contouring
the stock intake and charting the improvements on the flow bench, the students realized marginal gains.
The School then acquired an aluminum intake manifold with markings designating it as a GM
prototype from 1993. Further investigation showed that this was not simply an aluminum version of the
stocker, but a higher–performance variation. The team cut the floor out of the plenum and found shorter
runners and a larger plenum volume, similar to the current LS6 intake manifold. Untouched, the aluminum
version outflowed the stock LS1 intake by 20 cfm, and after massaging it a little, the team found another
10 cfm. With this casting, the Camaro generated consistent 11.30s at 121.5 mph.
After making extensive modifications to the ports in the stock plastic intake and finding minimal gains,
the students procured a prototype cast–aluminum manifold, which they cut open to reveal a larger plenum
with shorter runners. Flow–testing showed 20 cfm more than than the stocker, and porting at the school
picked up another 10 cfm. This was good for one tenth and 1.5 mph at the track.
