Corvette Magazine

Cylinder Heads. Also note that this increase was achieved with stock 1.94" intake and 1.50" exhaust valves in place.
After reviewing data accumulated during the dyno, Osucha felt that the stock intake system was restricting air flow. To alleviate the "cork," he removed the screen from the Mass Air sensor and installed a TPI Specialties air cleaner lid (part number 100-347) along with a low restriction element. These changes proved Osucha’s theory to be correct as horsepower climbed to 327 and torque nudged up to 342 lbs./ft.
Switching from the stock 48-mm throttle body to a 52-mm model, (with TPI Specialties airfoil installed) eliminated another airflow restriction which translated to an additional seven lbs./ft. of torque and 14 horsepower. In this form, the engine was churning out 339

Another key to any LT1 power combination is the camshaft. The ZZ9 is a proven profile that performs well in stock and modified engines, offering smooth power from just above idle to over 6,000 rpm.

horsepower and 348 lbs./ft. of torque-- increases of 46 horsepower and 17 lbs./ft. respectively, compared to the stock engine.
Pursuit of power increases in a stock-type engine is in actuality a hunt for restrictions-- corks in the parlance of the dyno room. Each time one cork is eliminated, another becomes the governing factor. At this stage, the two remaining corks of major significance were the camshaft and exhaust manifolds.
The most famous cam for LT1 and L98 engines is the ZZ9 from TPI Specialties. This amazingly versatile cam pays handsome power dividends when slid into the cam bearings of either stock or modified engines. Along with the cam, Osucha installed