When we built the 383 that now resides in the editor's ’72 Corvette Stingray, it was designed to be the cheapest build possible. From carb to oil pan, the entire project was under $3,500, including purchasing the block and machine work. The engine made some 428 horsepower on the engine dyno, but installed in the car, it fell off to 285 at the wheels. Not surprising considering the car's running through closed exhaust and turning V-belts (including one for the Vintage Air compressor). Most people don't realize how inefficient these old drivetrains were (M22 4-speed, IRS with 3.70 gears, etc.)
The flat tappet cam we used was pretty aggressive, but the 195cc heads were, let's just say, definitely of the budget variety. So, we got to thinking: Maybe it was time for a hydraulic roller cam and cylinder head upgrade. For a cam, we went with a Crane grind that had the 238/242 duration at .050 (vs. 234/244), and .588-in lift intake and exhaust (vs .488/.510).
We got the cam in yesterday with the help of Greg Lovell of Anti-Venom High Performance (Seffner, Florida). Still running the low-dollar heads, we picked up 11 rwhp and almost the same amount of torque. The big difference, as the graph attests, was the power under the curve. The new cam was better everywhere, but at some points we picked up 20 lb-ft of torque and 18 horsepower. That's usable power you'll really feel around town. Not only that, but the idle is smoother, there's more vacuum to assist the power brakes, headlights and wiper arm door. You can see, we're completely out of steam above 5,2
Today, Greg's swapping on our Airflow Research 195cc heads. AFR says we'll pick up a ton of horsepower and prove not all 195cc heads are created equal. The full story on this head and cam swap will appear in the November '13 issue of Super Chevy Magazine
For the back story on the engine in the car, search "Shoestring Stroker" on superchevy.com. There were three installments, including the dyno test.