valvespring upgrade questions
If that's the cam you want by all means run it. Get the cam and take the heads back to the machinist with Part# 73943K1 for the spring kit. Like I said he may know a replacement spring that will work with valves. This is the most cost effective way. If you can find a set of Vortec's that would be the best thing to do. Most likely you have dished pistons and they would give you a boost in compression. About 50hp from the heads alone. You'd still need the valve springs for the Vortec's and cut the valve guide bosses for the higher lift cam. You would feel the difference. I don't think you would get no more than 300hp out of the 624's.