Do you have an insulator under each Carter?

How are you heating the Offenhauser intake?

You'll need a LOT of energy and a LOT of $$$ in order to plop an LS3 onto a different chassis. This does not sound like an easy solution.

I had two Rochesters on a Offenhauser water-heated 261, with no problems since 1997 (now owned by a friend).