I'm building a 302 and I'm going to run 65 289 heads on it. These are early heads with no thermactor bumps. The Machinist is a close family friend and is basically doing the work for free. My plan was to put 351 Windsor valves in, he was getting ready to do them today and he said that the installed height on a 351 valve is taller than a 289 or 302. Is it enough to cause an issue With valve train geometry? He already installed threaded rocker arm studs so they are adjustable. He's basically waiting for me to give him the go-ahead to put in the hardened seats and new valves.