I helped a buddy of mine modify a 203 Ford Lightning 5.4L. It had a lot of power,but now it had a engine rebuild and port and polish, we added bolt on, the supercharger ported, added Nitrous and other sorts. We adddd Royal Purple ATF too,but is the factory fluid shot or on borrow time. Quarter mile time is in the 11's? The NOS is a 150 shot and fill is M1 5w20? Is the rear end due for service and if so what fluid/weight?