I am curious to see what those heads end up flowing. And what the cam ends up being.
Did you ever get the chance to do a compression test? IF you did I must have missed it. But with your setup if it's not cranking 190-195 minimum. Then you have DCR problems. In an aluminum head setup 190-195 = 9.5 Dynamic compression ratio. Which is the "theoretical" safe max limit for pump 91. I'm correcting for your altitude (I believe you said 1000 feet?) And yes, there's guys running 220 psi on aluminum heads on pump gas. I'm just giving you the idea for whats the "safe" limit. But something tells me, you're going to end up down in the 175-180 PSI area. More around 8.5 dynamic compression. Which can end up giving you a "soft" bottom end. Of course "soft" is relative. 8.5 DCR is stout. Just not near the max what an aluminum head engine can do.
As a side note. I was reading the thread where MRL just did a somewhat similar build. 416. Flat top. 10.8:1. FItech EFI. Hughes big mouth heads. RPM dual plane. Solid roller with 281/285 duration at seat. .620 lift. It made 582 TQ at 4350. 584 HP at 5800 rpm. Torque was 525 at 3100. And 550 at 5500 rpm. And that was with fuel pump problems at the top end. He thinks it should be closer to 600 horse with the pump working properly. So smaller cam. "Bigger" heads. Dual plane intake. But still a little more than what your's did. And to be honest even with the "better" flow numbers of the big mouth heads, I can't think that has a HUGE impact at your power levels. Even according to hughes own flow charts. Anything over .400 lift the big mouth only flow around 10 CFM more. WAY inside the 10% someone mentioned hughes said was their "error margin" for flow numbers. Even at lower levels the flow increase never exceeds 20cfm. That's on their own flow charts. 10% at 250 cfm is 25cfm. Meaning the CNC and big mouth heads COULD technically flow the same. Since hughes apparently doesn't flow heads after they port them. Just looking at your build. To me. There's no reason that thing shouldn't touch 600 horse.
I'm gunna wait and see what the cam/heads comes out too. It could just be a combination of small things. Head's not flowing quite what they say. Cam specs being a hair off. Intake could be better. Etc etc. If it was only one of these things, you might not even notice. But it's the old "death of a thousand paper cuts" where all the small little things end up causing one big problem. The devil really is in the details with engine building. I mean even something as simple as a better bore/hone with proper rings can pickup 20 horse.
So let us know what you end up finding.
