I put together a little chart , that I had with some head flow numbers here. The EQ's have been flowed by my guy Mike at High Flow, Jim Valako, and Scott Foxwell so far. While everyones bench can certainly be different, the numbers are starting to speak for themselves. All 3 of these EQ heads, have stock ports. Those are good, real world , not "advertised" or inflated numbers.

Full Force Tim's FULLY ported AFR 325's, flowed well too as you can see.. But, again, a set of afr 325's are 2300 set bare. EQ's, 900 a set bare. EQ heads have powdered metal valve seats, the AFR's, Ductile Iron.

I'd like to see someone like Valako do a full port job on these, and see what happens. Getrdun?

Mild, Jim V # for exhaust flow at .8 was 300. Sorry didn't include that one in earlier post.

I'm certain he has fully hand ported EQ numbers. Jim will typically give a guy the best bang for the buck so to speak unless specified by who he's doing the work for. I can appreciate that as after a point you can spend hours a heads chasing just a few cfm. Not real cost effective nor performance in reality. Those are some awesome numbers as posted. ive known Jim since the old epoxy floor days back in late 80's. He simply does great work and is honest as they come. Many other good head porters and engine builders as well but I just happen to hook up with him way back and have a great relationship.

I'm curious to see where he comes in at with the promaxx. I knew he was getting pretty good numbers with the EQ's. I will start another thread with Promaxx numbers. If there's no casting flaws or issues and flow similar to EQ's that will be great. Will always be a place for darts, afrs, brodix but glad to see some others getting recognition for a couple of reasons. It might just drive some ot the others pricing down and it makes a build more affordable with same same results.

will you have numbers for the promaxx prework for a baseline?

Oh for sure. It doesn't take long and wouldn't even consider not. That's part of the pride and bragging rights. Lol.

332's. ;)

I'm not getting it? You mean the 332 Brodix?

From Chad Speier , thought I'd post it. Good info

This is probably the most asked question I get. What size head do I need?? While head CC's are a by-product of a properly sized cylinder head, there are mathematical formulas to lead you to the correct answer. There are many reasons that choosing a cylinder head based off port volume is a bad idea, simply put there are 100 ways to arrive at a port volume!

First off, CC's or port volume measurements are “close guesses” to a ports average air speed only. It gives no insight what so ever into the ports velocity profile. CC's came about in the 60's when the heads where to small so the larger the port, the more power one could make. Head porters still use CC's as a quick dirty guess as the average air speed in the port, that’s all.

With three know things about any cylinder head, we can arrive at port volumes. Knowing this along with a program such as Pipemax, we are able to choose cylinder heads in a way they that is proper and logical. It's all about average velocity in the induction, 260fps is a great starting point!

Most cylinder head porters are working off a desired MACH speed of the port. 1116 feet per second = speed of sound @STP or .55 MACH. You can design ports slower than .55 MACH, but it's usually considered the speed at which "choke" or "port limiting velocity" occurs in a running engine.

613.8 fps = .55 MACH


So let's look at the important things we must know about our cylinder head. We need to know the following in choosing the correct cylinder head:

"average" intake port length (roof length + floor length from seat ring to opening) divide by 2
port volume cc's


Then we need to look at bore and stroke and desired RPM in selecting the cylinder head. The correct formula for determining how big of cylinder head we need:

MIN CSA = (bore x bore x stroke x RPM x .00353) / 613.8 (.55 MACH x 1116 fps)


Let's build a 434 SBC turning 7000 rpm. 4.155 x 4.155 x 4.000 x 7000 x .00353 = 1706 / 613.8. The formula says you need 2.78in²²²² of MINIMUM CSA to achieve your RPM goal...

Now let's turn your MIN CSA into a CC's for choosing a balanced cylinder head. Remember from above, I said you needed to know port volume and average runner length! Now let's put those into out formula:

Port Volume CC's = MIN CSA x Port Length x 16.387


Most SBC cylinder heads are in the 5.45 port length. Again, roof length plus floor length divided by two. So 2.78 x 5.45 x 16.387 = 248 CC's... Our math is telling us to achieve 7000 rpm from a 434 cid, we need 2.77in² MIN CSA and port volume of 248cc...

The key to any cylinder head is a balanced port. We are trying to balance it around a MIN CSA to achieve proper filling. SRH designs and ports based off velocity profiles. Although formulas are nice for "ballpark" sizing, localized and average velocity is KING!


I get this question PM'd to me all the time so I though I would take some time and show you how it's really all about AVERAGE AIRSPEED in the induction.

Two totally different cylinder heads, different flow curves, different port volumes, but yet the same average airspeed.

I'm going to use my CNC heads for the examples (because I know they are correct FPS vs AREA vs CFM)

Head #1. v2.70PF.. Flows [email protected].. 250cc port.. 5.47 long
Head #2 v2.50PF.. Flows [email protected].. 227cc port.. 5.45 long
Manifold Holley 300-110 in AS_CAST form.. short runner=4.625, long runner=5.500
short runner pours 215cc.. long runner pours 240cc

FORMULAS:
Average CSA = Port Volume CC/ (Port Centerline Length * 16.387)
FPS= (Flow CFM * 2.4) / Average CSA

Head #1 flows 320cfm through manifold and carb
Head #2 flows 305cfm through manifold and carb

Head #1= 465cc short runner.. 490cc long runner
Head #2= 442cc short runner.. 467cc long runner

Head #1= 10.08 short runner.. 10.95 long runner
Head #2= 10.10 short runner.. 10.98 long runner

Head #1= 10.08 x 16.387 = 165.2 / 465cc = 2.81 avg CSA short runner
10.95 x 16.387 = 179.4 / 490cc = 2.73 avg CSA long runner

Head #2= 10.10 x 16.387 = 165.5 / 442cc= 2.67 avg CSA short runner
10.98 x 16.387 = 180 / 467cc= 2.59 avg CSA long runner

Head #1= 320 x 2.4 = 768 / 2.81 = 273 FPS AVG VELOCITY short runner
320 x 2.4 = 768 / 2.73 = 281 FPS AVG VELOCITY lon runner

Head #2= 305 x 2.4 = 732 / 2.67 = 274 FPS AVERAGE VELOCITY short runner
305 x 2.4 = 732 / 2.59 = 283 FPS AVERAGE VELOCITY long runner

NASCAR. with the rec ports and 320 runners 8k plus rpm.

Ok let's take a stock 454 / 365 mag build. With your formulas what size runner would be let's say adequate running at 4,900 rpm.

My heads are all ported and flowed now, sure do look nice for a backyard hack job... a no name idiot.

[ATTACH=CONFIG]563471[/ATTACH][ATTACH=CONFIG]563472[/ATTACH][ATTACH=CONFIG]563473[/ATTACH][ATTACH=CONFIG]563474[/ATTACH][ATTACH=CONFIG]563475[/ATTACH][ATTACH=CONFIG]563476[/ATTACH][ATTACH=CONFIG]563476[/ATTACH][ATTACH=CONFIG]563477[/ATTACH][ATTACH=CONFIG]563478[/ATTACH]

so now you have a 335 cc intake port?

Just a guess? I'd hope not. Looks like they cleaned up well anyway. For tims sake I sure hope they work out. 305/315

According to cam people all of them, the heads are very nice heads and will be great, with the cam choices in front of me.... all 5 were very close in comparison, and every one of them homies what boat and how heavy it is, if it don't perform it will get boost lol

Its really not about port volume per say, its about CSA vs Flow and Velocity (FPS). For example, a Dart 325 head, will have a smaller avg CSA than the GM 990 325cc head. It also flows more air as well. That is why, when you bolt a Dart 325 head, in place of a GM 990 head, you see power gains. The port volume itself, means zero. It is simply a way to sell heads. Same for flow numbers. Anyone can hog out a port and make big numbers on the bench. But its the overall architecture of the cylinder head, that determines whether or not its gonna make power out in the field.

As a very general statement, yes, it is always better to use a smaller head, that flows as much if not more air, than the larger head. A 320CC head that flows more air from .200-.700, will make a better combo, than a 345cc head, that flows the same numbers on a bench. But, on the flip side, bolting on a 265cc head, that flows less air, but has a higher FPS, may, or may not, make more power than the 325cc head, if it simply cannot deliver the required amount of CFM, to reach the goals. This is why, you don't see anyone running a 6000rpm 800HP 572, with a 265 AFR head, or a 781 GM oval port. The head just isn't gonna get it done. If it could, everyone would be doing it that way.

A 4900 RPM 454, certainly does not "require" a cylinder head, with the CSA, or port volume, of the GM Rect port head. It is way off, from modern design. However, it is not like it didn't "work". Its what they had to work with back in the day, at the factory. The 454 mags were great engines in their day, and with the dual plane, quadrajet, and small cam, they pulled lots of skier's up out of the water, and powered many big boats. Especially considering they were low compression as well. Big ports, low compression, and they ran pretty decent. heck, that 990 head, has too much CSA, for even a 454 turning 6000RPM. But, there were a ton of those at the drag strip racing for the past 50 years.

From a comparison standpoint, what do you think a 5000rpm 454 mag with a 325cc head would be comparable to, if you were comparing CSA/Volume per ci, to say, a 540ci? It probably be like bolting on a 380+cc head on a 540 that turns 5000rpm.

I think most of us here, are looking for a combination, that makes respectable power, and runs well. Nobody is building competition engines here, where 12ft lbs of torque, or 14hp , is going to make or break the build. Its not nascar, or any class limited stuff here.

Is Tim's AFR 325 head a bit large for a 6000RPM 540ci marine engine by textbook standards, yes, they are. Would an AFR 305, or even 290, be better suited for the combo, yes, they would. But, what are we talking here? 80ft lbs of torque? 75HP? Heck no. If he swapped his heads as they are right now, for a set of 315's, with no other changes to the build, I really doubt he would see any seat of the pants difference in a 35 Mistress.

The goal was to maximize the parts I ALREADY have, I agree the 325 may be larger then needed, that being said that's what Bob sold me for my goals that were not met, so I maximized my parts for best possible case, new Intakes, portmatched, cams will be a huge change over old ones, and having actual flow numbers and more importantly WHERE the gains and flow is, that will help us chose proper cam and not guess...

All 5 cam companies we taked to spec'd almost identical cams, for heavy boat, and to push 5800-6000 IN THE BOAT, is the goal... to spin my props that I have to 6000 or as close as possible, the changes I am making should absolutely make some sort of difference and will be dialed in WAY BETTER then before and more then most combo's I see, my buddy helping me looks into every little thing and is very sharp..between him, Joe and myself I think combo will be as good as it can be.

This is by far not a hack job, or a guessing game like the recent Big Johnson story going on on FB...

My goal is decent power, and reliable, stable valvetrain and such...

Recent research shows me the ENDURANCE PAC springs that Bob sells with AFR heads are just hot rod street car springs, when my buddy called PAC yesterday to see what they actually are good for they said toss them and buy 1200 series endurance springs... again never will I buy a head assembled... good thing some guys been lucky but I was not, and now have some REALLY EXPENSIVE AFR heads...

I was on the phone with a friend the other night, an oso member, and one who has been around many hi perf offshore engines, for many years. He had a set of AFR's on supercharged engines. After not very long, he had some valves sticking in the guides. The guides were simply too tight for the application, and needed to be sized. That , along with better valve seats (his were very worn), were installed in the heads.

I'd like to see an engine Like yours Tim, that will make more power , with a 305 "as cast" out of the box, vs the CNC ported version of that head, the 315 AFR. or, in your case, the 325 "as cast" vs, the CNC ported version of that, being the 335. Even thought the port volume has increased, typically, the additional air flow overrides that.

Also, just because a head is labled a "325" cc, doesn't mean thats what it actually pours at. From Tony Mamo

Regarding the other posters question about the CNC bowls, whether you opt for the chamber or not (Can't stress enough how much you should), the bowls come CNC ported either way. Its simply included in ANY of our as cast product which is a nice plus about the AFR as cast offerings.

The AFR 325's are just the opposite of the 345's in the sense they run on the small side and usually pour in the 317-320 cc range. When you CNC port the chamber it explodes the low mid lift side of the intake port, and usually peaks earlier (a good thing) around .650 lift in the 375-380 CFM range. The low lift flow looks very similar to a 315 head as well, fattening up 10-15 CFM's across the bottom. Exhaust is up 10 at .200.....15 at .300, and carries 15+ CFM thru to you cant open the valve anymore.

how can you make a 325 port a 315?surly not from making it bigger.

Eq heads
 

I have a Set.

As I don't own a set I can't comment on their machining, but worrying about the rocker being centered over the valve tip is not going to cause valve guide wear like you think. You will get wear from a wider sweep from the rocker arm on a centered valve. On my Dart heads when setting up pushrod length I found the mid lift point of my rockers has the intake rocker sitting very far towards the exhaust side of the valve. But I also only have .024" sweep. Centering the pattern results in a nearly .095" sweep. My heads have lash caps so there is plenty of real estate for the rocker to push on so I am sending it. My other alternative would have been to buy backset rocker arms to correct the rocker tip placement, but for me I feel it is going to be a non issue.

I took his description to mean that the rocker studs were not on plane with the guides and the result would have been that the rollers would not sit perpendicular to the valve stem.

At what point, were you like, wait, the guides are off, the seats are off, on brand new heads, and still decide to move forward with them?

Milled the rocker stud pads? Did they also redrill and retap the rocker stud bosses ?

Not sure if you read the whole thread, but mine were completely gone thru, machined and assembled by a cylinder head shop that has done cylinder heads, amd only cylinder heads, for almost 3 decades. He has seen them all, dart, afr, brodix, gm, edelbrock, pro topline, trick flow, etc. He found nothing horrible about the few sets of eq heads hes done. They were chamber ported, new valve jobs, and so on. He is very anal, but he is also very honest. If they were crap, he would have spoke up about it. He had zero interest in whether or not they were good or bad, i didnt buy them from him. If anything, it would be in his best financial interest, to sell me on replacing guides, seats, and machining.

Upon assembly, i checked several valves while mocking up pushrod lengths, and recording sweep patterns on the valve stems. I found no eveidence of the rollers not sitting flush on the valves, even with checking springs.

Quite a few big name cylinder head guys are using this casting, and have cnc programs for them , and running them on some high dollar truck pull engines. It certainly sounds like you have had some issues though. Engine quest did chime in earlier in this thread, it be interesting to hear their take on the issues you had .

EQ
 

Which head is Vintage referring to? We have not received a call on this issue and would like to discuss ANY QC issue that you may have run into. Typically it would be best to call my line directly and we can go over your alignment issue. Is this a 502 he is talking about?

He is talking about the CH454A i believe, the 320cc version

EQ
 

Avoided you? If the heads came from this office there certainly would never be anyone avoiding you. My direct line to my desk is 800-426-8771 ext 209. Curious who you spoke with at our company.

I've never touched an engine quest head. The poster on the previous page indicated he had a problem.

understood. i found his post.

This guy, Post #180

time to man up and call them. Ive had a set gone thru and assembled by a cylinder head only shop and these guys were very happy with the quality. No issues with rocker geometry either.

Post some pix of your problems

I have EQ heads. They were just gone though. No complaints from him except the excess casting sand was a pain to get out on final wash. My only other complaints is spring pockets were not the size they were supposed to be. No big deal as they were machined also. We resized the guides, blended bowls, backcut intakes and new valve job. No complaints about the castings or how things line up.

Pocket Diameter
 

Spring pockets were moved to 1.550 about a year and a half back. I have alerted our marketing staff again and they will be adjusting all info listed on-line. Sorry for the confusion.

Eq heads
 

Deleted post out of courtesy

Eq heads
 

Deleted

Eq heads
 

So I talked to Eric today, he said if I have any more issues I could call him about it

Im not understanding clearly on the chain of events. You purchased the heads bare, assembled them, ran them, had oil pressure issues, pulled engine, then found issues with the heads? Am I understanding that correctly?

When you say you had the seats "recut" , was this before they were installed ? You earlier said the seats had to be REPLACED, was that before or after?

The 1200 dollars spent on them, was that soley in machine work?

The few friends I have that have purchased and used these heads, I strongly suggested getting them checked out and assembled by a professional cylinder head shop. Actually that goes for any brand head. There have been plenty of issues with out of the box name brand heads as well. Its no different than assembling a bottom end. You cant just order up a block from dart, and just hope the clearances/tolerances are good to go. Even a brand new dart/merlin block needs a bunch of machine work before its ready for assembly.

As far as cost, last time i looked, a pair of Dart CNC 335 MARINE heads, with inconel valves , anodizing, and assembled, was just under $5,000 a pair. And even then, i would still want to check them out before bolting them on.

I love turtles

Eq heads
 

Offer the heads with seats pressed in uncut and guide bushings uncut. Then it would be a great start point

Double post. My phone thinks it is funny...

Ok, sounds like a thread that was heading into the mosh pit just calmed down. Veloc410 just deleted 3 threads. Endeavor and SB both have quotes os the first one posted. Mild Thunder and ICDED both have quotes of later posts. He can't delete you guys quotes of his deleted posts. Only you 4 can. And I will edit this out and replace it with a stupid question after this is taken care of.