I am not saying use the 305 heads at all, only reason I used them is because a guy had spent 400 buck reworking, shaving and putting new springs, then wrecked the truck and and gave me the heads. I am going to run them until I rat hole enough money to get some better heads for myself. Either work the humps or buy some new. Here about a year ago I hauled all my spare 305 parts to the scap iron yard, I don't think I could ever bring myself to spend money on a 305 setup.