Naaaa, dont mess with the exhaust seats, just cut in the bigger diameter intake seat, it will interlock, but just retouch the seat when your done. Easy peasy. I like to tig weld around the seat insert, they just fall out when they cool.
i have two Tig welders and I wish I was better at it but number one I don’t do it enough and number two my eyes are good except for close up work. I’ll probably quickly mig a Chevy valve to it and punch it out. I don’t see me doing 8 seats on a set of heads I honestly don’t need. Problem is I already welded up one head and opened the pinch up .100
