well to be honest... I don't think the 4500 I have will perform as well as the carb in use. I put an adapter on my 4150 intake and ran our dominator and it actually slowed at Barona. ALSO... the 4500 intake I have was welded up and adapted with not much porting in the plenum area and the port size shape is still that of the craftsman based mill it came off. I will play with it as is with a port match one day. Until then....we'll continue with what we got.