The aluminum heads will help the compression issue a little bit, as aluminum can take a little more than iron. But, like COPO said, I would probably drop the compression about a point or so. Then, I would call the cam manufacturer of your choice, tell them what combo you are running, and let them put it in the computer and find out what you need. With the lesser compression, the original cam would be a real dog. Go with an aftermarket grind. Oh yeah, make DARN SURE you have a 4-core radiator and a good waterpump/thermostat!
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Rob Clary
'70 LS-6 Chevelle
Numerous Yenkos
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