We make 780 HP with 500 CI NA on the dyno at 6800 HP with 15.5" exhaust. Same geometry as the old APBA Super Cat engine spec's but with about 9 to 1 CR to run on pump gas. The heads are the Dart Iron Eagle 308 reworked by Jim Valako. The intakes are 320 cc and the exhaust ports were also improved. We ended up with intake and and the exhaust ports being equal to or very close to the AFR CNC 320. Iron heads should last forever in freshwater. "Forever" will come sooner to a few of us than than most sport boaters :eek:
Not may head porters are willing to work on cast iron....slow and dirty.

My heads were aluminum. The early race series heads. They dropped the 308cc after a while, but kept the 320 and 360cc version of the race series, even till this day.

That is some awesome power you guys make with the 308 iron eagles. Great cylinder head!

I didn't know AFR had a CNC 320.

The AFR website says 315cc, we are slightly above the AFR advertised port size. Things may have changed, but 10 yrs ago it was pretty easy to improve on the AFR exhaust port.

Would an intercooled small pulley hyd roller 525sc benefit from these heads?

FWIW, I had my Edelbrock Performer oval port heads flowed and these were the numbers;


Int#1
.400 lift 267cfm
.500 lift 295cfm
.600 lift 317cfm
.700 lift 335cfm

Ex#1
.400 lift 192cfm
.500 lift 212cfm
.600 lift 233cfm
.700 lift 244cfm

Not bad numbers on the EQ heads. The AFR's seem to have better numbers, especially when you add the CNC chamber. I guess it's gonna come down to what direction the owner wants to take this project. I finished building the short-blocks this weekend so thanks for the info.

I know the afrs he has flowed on the same bench , werent much better if any. Of course if you put a pipe on the exhaust, and a tulip style valve, the numbers go up.

Big difference is, the EQ head bare is 425 bucks. An afr as cast with cnc chamber, is around 1k each bare. Full cnc, even more.

It will be interesting to see how they flow , after some work and new valves. With a full cnc program, they are going 440cfm at 700lift . But, youre looking at 2600-2800 a pair , bare.

I paid $1350 for a bare 335 CNC AFR head. Awesome head and beautiful piece of machining but I am not going to build a max-effort engine again. Just a total PITA but was fun when it was completed. the extra few CFM just isn't worth it to me especially for the cost since my next project will be twins. Like MILD said, awesome flowing head for the $425!

Flow numbers are only a small part of the equation and not the most important. Most of these heads you guys are talking about flow a lot more air than you'll use in these combinations. Even supercharged. Port shape, cross section area, chamber design, getting the right cam and how well the head is suited for the combination will all matter way more than the flow numbers. Plus, you give me one cylinder head and five flow benches, and I'll give you five completely different flow reports. Just like dyno's. Flow numbers like .050 cam duration numbers are more relevant for advertising and spirited discussions than anything else.

Very true. My point in having any flow testing done, was purely for my own curiousity. The dart heads, on my 468's, with the rest of the combo, made 800HP with just under 7lbs boost at 6,000, on 93 gas, with a roots blower. I merely wanted to see how the out of the box EQ heads, stacked up flow wise, to the Darts, both having similar port volumes, tested on the same bench. Although, the port shape, like short side radius, throat diameter/ratio, and so on, are different. As far as the porting or mods to them, I'm leaving that up to my head guy, as he's been porting and doing nothing but cylinder heads, since I was in grade school . That stuff is above my pay grade. I do know he didn't care for the throat diameter to valve size or what have you on my old darts, and some other things the last shop did as far as finish work after installing new seats. I was happy with the combo as far as power goes, but like anything, wanted something different, and something "NEW". Being somewhat of a budget guy, with twin engines, dropping 7000 plus on new CNC heads ready to bolt on, just wasnt my idea of a good time lol. I think alot of guys spend the extra money for CNC ported heads, and skimp on other areas of the build. Like you said, sometimes, it just isn't needed for these types of builds. An extra 20hp per engine, won't do squat for my speedometer in my heavy old boat. That extra 1500 dollars, would probably be better used for things like prop work, better ignitions, or so on.

What I liked about the price of the EQ heads, is they would allow me to purchase them, and spend some extra money having them gone thru and set up for my engines. The valve job , the springs tailored to my setup, rather than a generic set of springs most heads come with as far as distance to coil bind, etc, which valves I want, guide clearances checked, and so on.

Thats true but you can also get the AFR's built to order complete with PAC spings, retainers, locks, seals, and good valves for about $2600.

When buying bare heads buyers still have to factor in how much you're going to spend on valves, springs, retainers, keepers, seals etc. After all that the prices are not far off.

I'm not nocking EQ or any other bare heads cost. I'm just saying you have to invest a lot more then the head itself and pay the machinist to set everything to your specs unless you have your own machines in the garage.

^^^^
Then you`re back to the out of the box heads (production line)vs. properly set up heads discussion.

Your local machinist can do way better than then an assembly line.... this is in fact if you have a guy who is good and knows what he`s going. If you don`t you`re better off with out of the box heads.
Mine and Joes heads done by the same monkey couldn`t pass for 5th grade machining, assembly and parts compatibility and in that case I`d rather have out of the box heads.

Ya well let me tell you about a lesson learned... Nothing like buying them assembled and "ready" then to spend even more making them right... As me how I know...

First time I saw the EQ BB Chev heads at PRI I thought they would be a player in the iron head market, especially for the price. I think you made a good choice.

Obviously, I know this, but you bring up a good point. Yes, a BARE head, will need parts and setup, prior to bolting on.

Competition products is selling this head completely assembled, for under 1600 per pair. They will install inconel valves if needed for an upcharge. I believe they quoted me an extra 160 bucks or something like that when I inquired.

http://www.competitionproducts.com/E.../#.VrqsYObLo-A

I am currently working out a package with my cylinder head guy on these. That will include super alloy ferrea valves, competition plus intakes, and various spring setups, all tolerances checked, and assembled to spec.

As far as the spring AFR uses, I was told you get a "PAC" spring, but then AFR said the spring was made by pioneer or something? If you can get an AFR 325 head, with a true PAC endurance spring, and inconel valves, for 2600 ready to bolt on, then that is a steal for sure.

By no means am I trying to start an AFR VS Engine Quest war here. Two totally different heads. However, I am kind of over the "AFR is only way to go " trend around here when it comes to cylinder heads. Dart, Brodix, and others all make good heads, at various price points.

That is the same valves I'm going with for my bare 308 darts. With isky 8205 sp springs, retainers, locators, locks, seals, guide plates, studs, decking, and checking and setting guide clearance and seats on top of cleaning up castings.......I'm looking forward to boating....

Cleaned up and restored to continue the respectful discussion.

So I was thinking about this.. not really alum vs iron, just heads in general... I keep seeing flow bench numbers.. Im guessing you would want the flow of the head to exceed the actual flow requirments of the motor, but by how much? is there more efficiency when the numbers are more closely matched?and how do you determine what the actual flow requirements of a motore are?

And does EFI vs Carb make a difference? I have too many questions... When your squirting atomized fuel directly at the valve/cylinder Does port velocity still matter or does it just matter that you get X amount of air into the cylinder ??

My top ends have less the 50 hours on them so not looking to throw them away but if I where to get a bare set of newer style round port head to get more flow would I be able to switch everything over. Or would it not be worth it and just wait till the next rebuild or brake to switch to the new ones?

I am not a motor builder by no means but after the last 22 thousand dollar engine project I am willing to give it a shot and try.... well with the help of some friends and all of you of course lol

They are the old RHS head from what I'm hearing.

I wouldn't put assembled heads on an engine without at least having them checked. Most common thing I've seen are tight exhaust guide clearances. not setup for marine or blowers.

Not sure... Do the EQ heads come with 11/32 valves or 3/8? Most performance heads are 11/32. If you have 3/8 you would need at least new valves, retainers and keepers.

Ouch!!! Wish I could make that much doing engine projects for friends....I might make it my day job...lol. We've all been burned at some point or another.

I guess my point is to buy them assembled, pay to have them checked then clearances the cost is more then bare and build heads...

Not always, it depends what kind of deals you can get on valves and springs mainly. Sometimes the packages are hard to beat even if they need a once over.

what if i told you guys the best head is not iron or aluminum!

11/32

I'd probably agree with you!

Basically, with a few improvements/changes. The casting was originally the Pro Topline. Same foundry is casting them in New Zealand. "Masport" foundry.

Chem milled Ti?

I do like Edelbrocks concept.. anodized heads with stainless intake and inconel exhaust. You ad the spring you need,, sort of half way between bare and built....

I just dont know how good they are.. I have seen posts saying they are slightly better than GM and I have seen posts that say they rock.

As far as steel heads go, they were pretty good back then. The rolled valve angle is a big deal.

At the end of the day, I'm gonna weigh all the pro's and con's with my buddy I'm building these engines for and have him decide.

I'd almost wish he'd ditch the MPI for a carb cause I can make an easy 600/650hp with a few known combos but I got what we got here.

Female ? for 98% of us anyway.

It was a lot that went in to that bill lol . To start I broke a lifter twisted a prop shaft so all new lifters for both full top ends new cam full taredown and check on one and full tune up all around new everything. It was one summer of use after getting the new toy and running the snot out of it lol

The only thing that was nice about having a shop do everything was you drop of the boat broke befor winter and pic it up in the spring running like new. If it wasn't to big for my heated garage it would be a different story.

I chose 308 iron eagles when I had to replace my heads for a reason not yet given.

My boat is a straight vee with a high x......about the last place I wanted to remove weight was from the ass end.

Yes, most big straight vee bottoms love bow lift. Ever notice how much tongue weight there is when you pull the engines out of the hull?

I see that someone is captain of their ship.

I put my Edelbrock flow numbers up in post #126 just as info for anyone wondering.

I ordered 2 sets of the eq320 heads posted above from competition products. They will customize the parts to anything you want. I changed to iconel exhaust valves and different springs. They seem to come with better parts than most off the shelf heads, arp studs, manley extreme duty valves etc. I guess I'll see how the heads look when they show up.