GM Performance Parts ZZ572 Power Curve - Power Moves

After we had the Edelbrock Performer Air Gap tightened down, we secured the Demon 850-cfm mechanical-secondary carburetor and the MSD HEI distributor.

We found very favorable results by simply installing the Edelbrock Performer intake. The torque curve flattened and widened considerably and peaked 400 rpm sooner.

The ZZ572 crate engine is equipped with 1.7:1 roller-rocker arms.

Roller camshaft designs offer more aggressive camshaft profiles and reduced operational friction.

For the third test, we replaced the existing camshaft with the 454/502 H.O. steel hydraulic roller.

To make certain our data was correct, McClelland double-checked the camshaft measurements with a dial indicator and a degree wheel.

This combination yielded the largest and highest torque curve, which peaked at 663.4 lb-ft at 3,700 rpm. The engine delivered 19 inches of manifold vacuum at 800 rpm with the total ignition timing set at 33 degrees. But what's especially amazing is at just 2,000 rpm, the 572 now had 595 lb-ft of torque. Granted, our peak horsepower numbers dropped from 648 to 549, but torque is what accelerates a car. We performed all of our testing with 91-octane Chevron.