[78w72]

Originally Posted by srmmmm

My automotive engineering professor at General Motors Institute was Jim Lyons, the man who led the Turbo 301 development team at PMD later on. The factory crankshaft would bend or crack at 280 horsepower, and there were no internal counterweights on it. It would be impossible to make the engine internally balanced without a custom crankshaft. What Pontiac was able to determine was that the bearing loads from combustion were greater than the bearing loads from the lack of counterweights. That's why they were able to use the light crankshaft I doubt the turbo version connecting rods would even be stout enough for those torque numbers.

280hp? Was that the non turbo crank maybe? The 301T cranks were different and had filleted (?) journals where the metal kind of rolled or blended into the body of the crank vs the sharp blunt ends of standard 301 cranks, made them a lot stronger. The guys making 350+hp on stock cranks & rods arent bending or cracking 301T cranks. The rods are the same basic design as other larger Pontiacs so should be able to handle higher torque, but obviously better to use better rods at that poser lever.