If I were building one and wanted to use these heads for your combo and gear, I'd do a 4.125 crank. The extra cubes will work the bigger ports a few 100 rpm sooner.

I think you can build a BPE 4.125 or 4.25 stroke motor for around the same as his 408 kit, I'm gonna do one next time


WIZE

World's Quickest Diahatsu Rocky (??) 414" Stroker Small block Mopar Powered. 10.84 @ 123...and gettin' quicker!

https://www.youtube.com/watch?v=-mWzLma3YGI

In Car:

https://www.youtube.com/watch?v=PjXcf95e6v0