The OS 91 FX is a dog. The ST 75 would out perform that. (I had one and couldn't wait to get rid of it)

If you could find an ABC 75, stick that on the Enforcer. Once you get to the 91's (which are most always ringed), you start losing the rpm's the ABC's are capable of.

You want performance?? Stick a Jett 90 in it...and then hang on!!

Gary