[R 70 Judge]

Originally Posted by mgarblik

At the power levels you are considering, I don't feel any Billet crankshaft from a quality vendor like Moldex, Crower, Wynberg, Bryant will be any issue at all. Honestly, a Molnar forging would be fine as well. I have used all the ones mentioned personally other than Bryant and Wynberg. As far as stroke, we ran 4.50" stroke in IA and IA 2 blocks for years @ up to 1500 HP and never had a crankshaft or bearing failure. That was nitrous boosted. The long stroke was pretty hard on piston skirts with lack of support at the bottom. I prefer 4.25" stroke if given the choice. A square engine, 4.25"X4.25" is a nice compromise with 482 inches for excellent torque, better skirt support, more cylinder wall material and sealing area. I feel that's the sweet spot for these engines. Not sure what the attraction would be for a shorter stroke in a Pontiac race engine? Rules requiring a smaller displacement? The desire to run it at very high RPM's? We ran our 482 Cu In engine at 8400 RPM's without issues. That was with a roots blower.

Curious, is there a preferred rod length with that stroke?

[mgarblik]

Originally Posted by R 70 Judge

Curious, is there a preferred rod length with that stroke?

To get the compression height we wanted and provide room for the large pins, {1.031"), we used 6.7" aluminum connecting rods. I don't really know if they were optimal. We had Bill Miller as a consultant on the roots blower engine and that's what he felt comfortable with. No issues.