Performance Parts - Dyno Thrashin'

We Bust Out the Wrenches & Bust a Few Knuckles in Search of Bolt-On Horsepower

John Nelson Mar 28, 2008 0 Comment(s)
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Crossover Pipe
The bolt-on
Flowmaster Scavenger Crossover Pipe added into a Flowmaster Delta Force 3-inch dual exhaust system. $187

The mule
A '67 SS Camaro with a 10.5:1 compression 385ci stroker small-block running an Isky mechanical street roller cam, ported World Sportsman II heads, a ported Edelbrock Victor Jr. intake manifold, a 750-cfm Holley Pro series carb, and a T-56 six-speed trans. Power measured at the rear wheels.

Our take
According to our own Kevin McClelland, "The purpose of the Flowmaster Scavenger Crossover pipe is to increase the exhaust gas velocity in the large 3-inch system, providing a torque boost along with a few extra top end ponies." Looking at the numbers, that's exactly what happened.

0804chp_08_z Bolt_on_spacer 3/15

Carb Spacer
The bolt on
Wilson Manifolds 1-inch open carb spacer. $82

The mule
A 10.2:1-compression 540ci big-block with a hydraulic roller cam spec'd out at 0.566/0.566 inch lift, 242/248 degrees duration, and 112 LSA hydraulic roller cam, along with AFR 335 CNC ported heads, a Performer RPM Air Gap manifold, and an 850 Mighty Demon carb. Power measured at the flywheel.

Our take
Open carb spacers increase plenum volume, which usually leads to increased mid-range and top-end power. That's the effect the spacer had on this engine, at the expense of the peak torque; on the other hand, average power was improved. According to Westech's Steve Brul, some combos like a spacer, some don't; you have to try it and see. This one liked it.


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