A 904 would be my first choice, too, But would need a bit of extra attention to detail and a few better parts to give extended service with your engine. That would cost some more money.

A 727 would handle your power with just good stock parts and a shift kit, so it might be a bit cheaper. There are tons of local re-builders that can give you a quality re-build on these trannies. Our local guy will re-build them for $1,000 or so depending on parts.