Another 302 Head Question

I would run what you have, 675"s, Mill and prep them the same as I said above. Get Stainless steel exhaust valves and have a good valve job done. As I understand it, typical exhaust valve material is Stellite, sp. The cast iron from the seat sticks to the valve and then acts as a hole cutter and drills the valve into the seat and down. The cast Iron does not stick to the stainless steel and there is little erosion. Also the metallurgy of Mopar cast iron is better than lesser brands. I would not take the chance on installing exhaust valve seats unless there was a problem. You can cut into a water jacket or if not machined properly the seat can come loose.