Assembling my new engine after an A-1 rod bolt let go. (Long boring story). Did not damage the head or valves and the engine/head has "low" miles (6K) but they are all hard track miles...aka lots of fast laps. I pulled the valves and am not happy with a few valve seat blemishes.. so I'm going to cut the seats and have the ports cleaned up. I'm thinking of going to the Supertech STD valves and single groove keepers as an upgrade for durability/strength. What say those who have been there/done that? Thanks.