You can run any cam on 90 pound springs. The problem is to what RPM... in autocross you are slamming 2 gear to beyond redline for 60 seconds at a run. Then what is the rear gear? This will help tell what your RPM is going to be at 60MPH. Next what intake manifold and what size throttle body? The Ford manifold is designed to quit flowing at 5200RPM, they will rev to the moon if the heads and throttle body are big enough but the rate of rise is slower, limited by the manifold runner length and size. A big cam in autocross causes the "lightswitch" effect, the RPM gets high enough and wham your in the powerband for that cam and slamming the brakes and you just turned off the lights. In racing slow is smooth and smooth is fast, being able to both accelerate and compression brake the car with just the gas peddle is smooth and keeps you from using as much brake which upsets the balance by transferring too much weight to the front end, then you start all over at the next cone, a very manic car is draining to drive fast. The fast cars I see are easy to drive and look slow and do not look and act like some one has wasps in the cabin.
