Rev,
Sounds like you didn't have the chance to tune with the heads, and I'll bet tuning could make a world of difference. You had cast iron before? As you probably know, Aluminum can handle a lot more timing. It wouldn't surprise me if you upped the initial another 2-3 degrees without problems. I'm confident you'll feel the improvement.
Also, it's been a long time since I played with a Holley, but wouldn't the jetting requirements be different with the new heads?
L8r
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Russ L
'91 LX - 331 w/ Procharger
'03 Cobra Convertible - Pullied
'94 Lightning
'65 Mustang Coupe
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