And here’s just a tad bit more info on Jim’s 318” Y. We were rewarded with peak values of 429 horsepower and 388 ft/lbs torque and it didn’t take a whole lot to get there. The engine is a 292 block bored +060 (3.810” bore) and a 292 crankshaft offset ground to 3.480” stroke. The heads are unmodified Mummert aluminum units while the intake is a stock out of the box Blue Thunder. The carburetor for the 429HP run was a 750 vacuum secondary Holley. The static compression ratio is right at 10.0:1 while the camshaft is a custom Isky grind that has 270° advertised, 242° at 0.050”, and is ground on 107° lobe centers. The camshaft itself is installed at 2½° advance.
Here’s another duplicate YouTube link for the dyno pull.
Jim’s 318Y on the dyno
I’ll add that even at 318 cubic inches, the 750 carb that was being used is sized just about right as the 625 cfm carb that was also tested was showing a vacuum increase in the upper rpm band. That by itself is a very good indicator that that particular carb was undersized while the horsepower increase with the larger carb was another indicator. There will be a full article with more details about this engine in a forthcoming issue of the Y-Block Magazine.
Lorena, Texas (South of Waco)