March 1, 2009

If turning left and right on a road course wasn't unusual enough, Part 3 of our budget road race project deviates even more radically from the typical Muscle Mustangs & Fast Fords street/strip project car. For this project we're running as close to a bone-stock 5.0L as you are likely to ever see in the pages of this magazine. But since the Camaro-Mustang Challenge rules limit rear-wheel output to a maximum of 230 hp and 300 lb-ft of torque, we just didn't need to get very tricky with the engine.

Despite the '87-'93 5.0L H.O. engine's nominal factory flywheel power ratings of 225 hp and 300 lb-ft, it's possible to come very close to those numbers at the rear wheels with very slight modifications. Virtually everything in, or on, our engine is stock, from the oil pan to the intake manifold, including the 1991 H.O. roller camshaft, the E7TE iron cylinder heads, the stock tubular exhaust manifolds, the stock SN-95-style upper intake manifold, MAF sensor and throttle body, and even the stock airbox and filter. The only significant deviations from factory equipment are an underdrive crankshaft pulley, a BBK off-road cross-pipe with open-exhaust tailpipes, and the conversion to a Fox-style A9L engine computer with a Painless Performance wiring harness.

We did this to eliminate the SN-95's funky fuel and spark timing maps, since the CMC rules prevent using any aftermarket chips or tuners to reprogram the computer. As a result, we're stuck with the notorious rolling idle from the mismatch of the SN-95's 60 mm throttle body and larger 70 mm MAF sensor with the Fox computer, but the combination runs at a very happy 12.5:1 air/fuel ratio at WOT, just a tad on the rich side, which isn't a bad thing for this application.

On C&M Performance's Dynojet chassis dyno in Hubertus, Wisconsin, we made 225 hp and 294 lb-ft of torque from this combination, just a hair under the maximums allowed, and very robust numbers for such a stock 5.0L. We attribute the healthy gains primarily to the abbreviated accessory drive system, removal of all smog equipment, and open exhaust system from the stock headers back.

Ultimately, this will give us plenty of power to get off the corners, plus the reliability to go a season or more without a rebuild. Also of importance is having a proper transmission and rear, so we'll tackle that in Part 3 of our CMC build.