Originally Posted by dave1969chev
It will idle extremely rough and die unless I hold the throttle, no power at cruise, alright at wot but still not as much as I thought a head swap would give me. I tried throwing a 750cfm on it and it just blew rich smoke and wouldn't hold an idle. But I figured that was bc of the high alt. With my old heads I never had a issue with running a single plane, it behaved on the street.
You have a basic problem like valves too tight or firing order wrong, etc. If the heads are too big, which I doubt, it will just be lazy at lower RPM. It should idle at least as good as it did, especially with more compression.