[DavidNJ]

And back on topic, Genesis says they have 4 customers running the 4.5" stroke. It requires minor clearancing.

They get theirs from Scat or a local supplier with slightly longer lead times but slightly lower prices.

Many people have thought that the 4.5" may not clear the cam without going to smaller rod journals with matching rods, but however it does.

If going with a custom billet crank, going with the smaller rod journals is still an option. It apparently reduces friction and wear and is more than strong enough to handle the loads. Crower, Carrillo, and others can readily build the rods.

And if getting custom rods and custom pistons, you can probably go to a smaller pin....927 or even .866 or .827. This would reduce the piston compression height issues. However, with a 6.7 rod and 10.15 deck height, the 1.2" compression height should be ok.

But to net it out, a 4.31 bore, 4.25 stroke with Edelbrock heads is inexpensive way to build a solid 496 FE. If going bigger, you can get bigger heads and a 547, but will spend $5-10k more.