Seems like the low deck 390 block with the offset ground 401 crank for 421" would be the best combo. Kind of like the AMC version of a 451 B motor.

but I guess 390 blocks are more rare than 401's


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