Ok, I've used the search as much as I can and cannot find any answer posted for this question...for an 89 IROC with a 305 TPI engine, what makes the difference between the auto trans version having 195 hp verses the manual version having 220 hp? It is the ECU or cam or something else?

 

Ok, nevermind...I found the answer on a different Camaro site...auto trans engine had less lift and duration, but tighter lobe seperation...so less hp and more torque. Apparently the one other version (third option) had 10 more hp because of the dual-cat exhaust option.