904 or 727

I agree on rebuilding the 904 and keeping that. As stated, 727's are a little heavier, require more power to run, and there's a good chance you'll loose fuel mileage. Give John at Cope Racing Trans a call and he will be able to set you up with everything you need for that 904. They can handle alot of power. :)

I prefer the 8 3/4 rear over the ford 9inch. Since you already have mopar engine and trans, it'd make sense to have a mopar rear! :)