I have a 5.0 non- high output engine that I'm working on. then engine is stock except for a cold air, muffler, and minus 2 cats... its non M.A.F. system for the E.C.U.  My next mod is going to be roller rockers with 1.73 ratio and a 3/8" upper plennum phenolic spacer. Any body have expirience with these motors? What should my next mods be? How many mods/what can a person do with out recalibrating computer?.....

Thanks,
Brock  

i would switch to mass air then you can change camshafts to power levels your wanting