If I bought a 312 with twin 6.2s could I upgrade to twin big blocks without doing any transom/stringer work? Is the stringer and drive spacing the same in the small block and big block version? Thanks very much..

Whats wrong with the 6.2s?? Put a blower on them..be cheaper in the long run.

I know if it has bravo transom assemblies they will work with a big block.

Do you know if its a bravo or a alpha set up?

I would build the 6.2s to about 450HP a side. Small.blocks are cheaper to build and much lighter

I would think the drives might be right, but the exhaust would probably be different for sure. Not saying you couldn't work around that though.

I am sure the exhaust would need redoing but the stringer spacing and transom cut outs is my main concern.

Without some more specific info, I think Formula's use of motor plates would make this possible. Meaning the adjustments should be more like plates and mounts rather than stringer etc. I think the stringers are the same regardless of power.
I looked at a 312 with 502MPI and it did 71mph.