small block 350 trouble

[goob8869]

I ordered a kit of procomp aluminum heads and cam, and after installing it the engine runs and sounds great but is lighting the headers cherry red after just a few minutes. Does anyone have any suggestions on what I could do to help solve this. It is about 420 hp and is running on pump gas with a Edelbrock 600 cfm carb. I haven't put a timing light on it but it is pretty close turned it until it was starting real easy.