Thanks for the advice guys I only autocross this thing 10 times a year tops and what about a lsx 427 but I think I would still have to swap exhaust out.I auto cross with a fast bunch of guys and 2 of them have small block chevys and there about the fastest out there a ls would be nice but I would have to scrap all the stuff I all ready did for the car like a complete march serpentine pulley set up and my quick time bellhousing and custom side pipes.