Its your 264 exaust cam thats holding you back, big gulp of air(272 I) and not enough exaust cam to breath it all out.

~John

I must admit I have never heard of 272 intake with 264 exhaust. I would like to get a set of HKS 272's but then I would want to get new valvetrain(
likw 1mm oversized) and then springs and retainers (crower maybe ) and extreme headwork to go wtih it. But i would only do that if I had a built 6 bolt to put it on top of, and blah blah blah I would want to do that along with a built tranny all at once.