Quote:

.......is there any great advantage (rod ratio etc) in swapping to a 6.250" rod, considering this will not be an all out race engine?




No. Even in a complete race application, the difference
would be negligable. However, since you say a custom
piston is required either way, I'd do it. I usually build
what I want, when I'm paying for it.

IIRC, Don Gentry(B3422W5) used a 6.250" rod in his 4" engine. I'm
sure, it's been done many times. There is no downside to using it
in your case.......Cost being the only factor.