I am in the planning stage for a 528 or a 572. I have a world block which will be 4.500 bore. I have stock cast iron heads. I don't have crank,rods, or pistons yet. The question is should I make it a 528 or a 572? I am definately using the stock heads but will do a mild port to them. Will the stock heads flow enough for a 572 or would the 528 be a better choice? Any suggestions?

I had to edit my response as I guess it wasn't very clear. Stock heads aren't very good on the CID they were designed for,why build larger and think it won't be a bigger restriction? If you don't want to make HP they will be fine.

From what I've read the stock heads were oversized for a 426 and the 528 makes better use of the potential that is there. I'm not sure if a 572 crosses over that line.

LOL. I should really slow down and read everything before I respond.

So the stock iron heads, mildly ported, would work better on a 528 than a 572?................................ Or should I put them on a wedge? Ha,,, Sorry Goldmember,, I just had to add that.

I would call Dwayne Porter, Porter Racing Heads, or Jeff at Modern Cylinder Heads and talk to them. I know diddly about iron Hemi heads, but I am reworking a 528 crate motor. The aluminum MP heads on the crate(not the newer EBrock) flow barely 300 cfm on the intake. after CNC porting they flow 440. I don't know if these heads are just lousy, or if the older iron heads were any better, but if that is all they have, you are going to need a full port job to take advantage of either displacement. Just my .02.

Street car , stock iron heads , I would go 528.

i was told by a mp rep at the nationals several yrs ago that the alum hds used on the 528s were just out of the box alum hds with no additional work done to them. if that's the case other then getting rid of some lbs they should flow about the same as any stock hemi hd, right? 3ddart

I would do the 572 and just do a little port job like you said, then a couple years down the road when you have the itch to go faster you pull the heads and have them profesionally ported and add a bigger cam. Hemi heads can flow incredible amounts of air even in stock form.

I am doing something similar with my small block, as many cubes as I can afford (414)
Wiseco forged pistons, billit crower rods, mopar forged crank... and the heads I have are good for mabey 500 hp but the short block is super stout for later upgrades, I think my block will be the limit. When I get the money RyanJ will port my heads add bigger valves and I will put on a single plane and bigger carb and cam.