I currently have a Gen 6 540 short block, all forged rotating assembly, flat top pistons, 9.25 CR. Bob Madera cam that is .620 lift intake and .608 lift exhaust .I am running a set of cleaned up/blended bowls Dart Iron Eagle 308's for heads. In my current rebuild I have added a bored throttle body and have done extensive work on the MPI intake by milling out the vertical runner dividers drastically reducing runner length and allowing room for the die grinder to greatly enlarge the remaining runners to suit whatever head I want.

With that said, I believe my 308's are too small and would like to step up to an aluminum head also allowing me to raise compression. I looked at the flow numbers for the AFR CNC335's and they look very optimal flow for my lift range than compared to the larger runner versions. Looking at AFR's flow charts, I would need to step up to a 377cc version to gain any significant flow.

I like the AFR's but am open to other suggestions from guys who have built some big HP 540's. Lets hear some opinions/results from you guys.

The 377's are way too large and the 335cnc are too. You could port the 308's or step up to a 310, 315 or 325 head. For a 325 head, I would suggest raising compression. Most of the heads have the same chamber size if not the larger 121cc. Raising the compression would help. You need to pop in some 10.5 to 1 pistons. Depends on your cash flow situation.
Canfield has released the new line up. They flow almost the same, if not a little better then AFR's. Foxwell motorsports helped develop the heads and are also selling them. They are a great head made in Ohio and not as expensive. They offer sizes from 310 on up. Canfield older heads were great, well built and flowed awesome.
Just give Foxwell motorsports a call, very nice guy and uses, Dart, AFR, Brodix, and Canfield. Which any would be a good choice.

I ended up buying a set of AFR 335's with a small chamber. I will be around a 10.5 CR depending on gasket choice. It should make some great power even if I have to spin a few more RPM to take advantage of the heads. I WILL be calling Bob for a new cam and going to full dry exhaust/headers.

Good luck and let me know it turns out. If you decide to throw a whipple on, those heads will shine. Good choice on swapping out cams. Usually it is hard to find smaller cc, when you do you pay extra for it. Glad it worked out for you.