Sounds good to me! I ran 9.70's with nitrous and lots of street miles in a 3400lb car with a 904 that had pretty much what you described, but I never changed the pump lug style. You don't need shafts, cases, bolt in sprags, or a billet drum with what you are doing. The diameter of the front drum in the 904 requires a lot more for it to do the 727 grand kaboom...but a blanket doesn't hurt if you are still somewhat concerned.