What cam should I get?

Sounds like Comps' 280 magnum cam. That cam has 280 duration and ..480 lift and Comp's rates it at 230@ .050. Same rpm range too. Anyways its still big for a 273 but I really think those small intake and exhaust ports will help out. Hey in 1967 those hot rod guys stuck a .510 lift cam in their 273 motor-no @ .050 # cause they did not use it at the time-and they loved it. Saids the motor idle sound was whap-whap-whap-whap