Welcome to CHR, Dennis!

Not a big Ford guy (like em, but don't know them too well..) but first thing that comes to my mind is the difference in physical size between a 302 and a 429. Dimensions on the engine are 29" long, 24.5" wide and 28.5 high for a 302. The 429 is 34" long, 27" wide and 30" high the 302 weighs 500# and the 429 is a whopping 720#. The 302 is snug = a 429 would be a major project and dump an extra 220 pounds on the front suspension.

I'd look at building the 302 - I know they can really scream and as Dave mentioned, the gang at Kenne Bell really know how to make these engines perform!

Let us know what you decide.

Regards and again, welcome,
Glenn