Hi: I run a Comp.Cam 35-238-3 in my 72 with a 351w 500cfm Holley, long tube headers, Comp. Cam roller rockers, c4 auto 3:50 gears and it makes lots of power and has a slight lope at idle, just enough rumpity rump to be nasty sounding, valve lift .493int. .500ex. w/ stock torque convertor.