One last question. Of the 502/509" MPI variety builds using the MPI intake which heads did you have the most success with?

If I recall (without going back and re-reading everything) you;re looking for something in the 550 hp range? Frankly you can do that with just about any factory big block head including any of the larger oval ports.
Discussing cross section and flow is not speculation. If a head has X amount of cross section and a given flow value, it is what it is and will be "right" for a given displacement and rpm. It's just numbers.I know that ideally, a 509 making peak power at 6500 needs a minimum cross section of about 2.7 sq in to maintain proper velocity in the port for good cylinder filling. Knowing what I do about cylinder heads, I'd "estimate" the cross section in the 320 head is near 3 sq. in. In my experience, that's a little large, but not excessively and will only hurt a little lower rpm tq which everyone says isn't a problem in these apps. Properly cammed you might not even see the difference from a smaller head. The EQ heads have a nice shape to the intake port and chamber which is a big factor. When you look at hundreds of cyl. heads a year like I do you learn to see things and use your experience and intuition. It's not speculation.It's what I do for a living.

Not an odd question at all. We flow heads and intakes regularly for higher end competition builds. For the absolute optimum in camshaft design, we want as many variables as we can get on the table. I don't develop intakes on the flow bench like I do a cyl head. You can ruin an intake manifold chasing flow numbers on the bench.I port intakes to a given dimension and they flow what they flow. For cam design it's important to know what the entire intake tract flows and the intake manifold is nothing more than the "rest" of the intake port. The intake port starts at the opening in the plenum, and ends at the intake valve seat. The overall length, size of the opening in the plenum and amount of taper are critical numbers.

Never built one with the MPI intake. My best hyd. roller pump gas 509 was with a set of ported AFR 305's and a ported victor Jr and 1000hp carb, made 770hp @ 6300 and 730 tq @ 4700. Car engine. My last 509 was the same...hyd roller, pump gas deal, Canfield 310's unported, Victor Jr unported, AED 850 dp, made 710 hp and 680 tq. Very basic engine.
I'd have to look at the MPI intake and take some measurements to give you my thoughts. The AFR's I did above are going on a 515 (4.53 bore x 4" stroke).

Thank you. If you have time to take a look at that intake, I'd appreciate it.

He's pretty much set on keeping the EFI setup. I'd rather be building him a 600/650hp package with a carb or a different EFI setup all togheter but I'm working with what I have and want to select the best matched components to make the most of what we have. That's why I mentioned about speculation in my above post. I'm not saying it doesn't matter or not relevant, I just want to put this thing together with something that's proven. The EQ heads might be ok but I don't think this threads intention was to promote and sell EQ heads. I just want the most efficient proven package with cost in mind.

By the way, my name is Frank Ungarten. I'm not sure who you are?

If you have any specific experience or have put together a combination for an MPI based build, please share your results. Thanks in advance!

I do know that most MPI setups, can make excellent torque. There was recent testing from a few pro engine builders i followed offline. These were using the 525 merc intake system. Mercurys 525, used a 315cc edelbrock rpm casting. With a short duration, very little split in the cam, and high lift, the engine made big torque numbers, but suffered power above 5300. The intake was blamed as being at its limits, and that attempting to utilize that intake system beyond that, would be of no reward. However, when that cam was swapped out on the dyno, the hp climbed to 5900, and the torque peak came up a bit, but generally made more average torque in the operational rpm band. This was done with less lobe lift, and more split in the cam, no change to the lobe separation angle.

Testing like that, is what gives us data to change , or learn the effects of the design parameters, and there are many.

Now, knowing that the edlebrock head has a 315cc runner, but isnt exactly a great flowing head. Now, my gut tells me you take those off, and stick a set of those heads horsepower 1 just posted hes working on, and with the right cam, i think it would outperform the other combo just about everywhere in the rpm band, not just above a certain rpm because of the 325cc runner volume.

I've read a lot of those posts as well, some good data. Articfriends has a ton of time on MPI's and seems to be the most knowledgeable with it from a home grown perspective.

I'm focused on my specific build though and those with specific hands-on experience with my setup. Thanks anyway for the info.

Scott Foxwell. I'm on a short lunch break...I'll post more later.