cutlassefi

Well the results are in, an out of the box Procomp vs an out of the box Edelbrock vs. the Edelborck with a 4 angle valve job and minor bowl work, just cleaning up flashing etc.

Intake Procomp, Edelbrock- as is, Edelbrock- valve job

.100 62 70 69
.200 127 133 136
.300 187 186 190
.400 231 219 238
.500 239 244 261
.600 234 255 264

Exhaust

.100 54 59 66
.200 96 103 112
.300 129 137 146
.400 151 159 169
.500 170 170 185
.600 180 179 195

All testing done by Champion Race heads in Palm Coast Florida, on the same day, the same machine, a Superflow, and by the same operator. Bore size was 4.155.
http://www.championraceheads.com/

Both heads were purchased in bare form. The Procomp came ready to assemble with the guides reamed and seats cut. The Edelbrock did not, the guides were unfinished and seats showed only a 45 degree cut. All Valves were back cut and all seat faces are 45 degrees.
These numbers are for comparative purposes only. Actual numbers will differ from bench to bench. In fact they informed me that if they had done this on their other Super-flow, it would have showed higher intake numbers but lower exhaust, go figure. But again both heads were done on the same bench, the same day.

Thanks guys!!

380 Racer

Good job Mark.........good comparison of results.

Rickman48

I think retail $$ amount, including machining and assembly, would be rather easy to post, as it should be fresh in everyones mind -

cutlassefi

Knock yourself out. Too many variables there. All I know is you can get the Procomps bare for about $800.00 a pair and the Edelbrocks for about $685.00 each.
Some people have commented that they don't think much of the stock Edelbrock springs etc any more than the Procomp stuff.

My recommendation would be to buy them bare and do what you want with them, either one.

jfb

hey seriously i do not see any listing there posted is that pro comp or edelbrock just post it right dude.

jfb

by the way i have edelbrocks stage one ported and i picked up on a rear wheel dyno about 67 at the wheels or about 83 at the flywheel jfb.

cutlassefi

What?

Boldsmobile

Thanks for the effort and sharing.

cutlassefi

Thank you Pete and Nick. I try.

MDchanic

What? What?

[that's double-what]

Thanks, Mark, for some helpful and valuable information for all of us, even those of us who don't expect to be in the market for a set of heads for a long time.

- Eric

TripDeuces

Nice work Cutlassefi. It's about what I expected - both within a few cfm of each other. To be honest I actually expected the numbers to be higher but still a nice comparison.

cutlassefi

Thanks, but remember all benches are different. I think it's a good comparison.
Also, when I get the heads back, I'll show pics where I traced it on the head surface. You can see how the Procomp heads' combustion chamber goes right to the bore size. The Edelbrock has just a little casting hanging into the 4.155 cylinder. That's what I used to trace it. So you might be able to message that a little for even a little better low lift flow on the Edelbrock. Just a thought.

oldspackrat

Thanks for taking the time to do this & to share it with us!

ah64pilot

What? What? What?

[That's triple what?]

Mark, great comparison! The flow numbers are so close, it's a toss up which one is better for the money. Are there any other observations you can provide with regard to cosmetic appearance, fuel pump clearance, etc?

So when do they get the competition port job and subsequent comparison? lol!

VORTECPRO

Thanks for the information. I feel a lot better about sticking with production heads on my build now. For some reason I just like trying to make the factory pieces work.

83hurstguy

Interesting info, thanks for posting!

Did you gain any insight as to why the ProComp intake flow curve goes flat over .400 lift? Just curious... must be a choke point in there somewhere.

VORTECPRO

The short turn needs to be laid back, notice that .400 lift number?

507OLDS

The numbers are as-expected,since the procomps are copies of the previous Edelbrock design.I assume you used the latest Edelbrock head? For that matter,the new is almost the same as the old.Thanks for taking the time to do the comparison.

cutlassefi

Yes the Edelbrock is the newest version. I will post pics when I get them back and I like the better exhaust port vs stock or even the Procomp. The Edelbrock is better all the way through.
The owner of this build is considering guide and short turn radius work. If we go further those changes will be flowed as well, and of course posted here.

One other thing, remember the new Edelbrock has a revised combustion chamber as well. No one knows quite yet what that does or doesn't add.

507OLDS

I believe the latest design,with the revised combustion chamber,is their 3rd design since they started making the Olds heads,or are these the 4th design?

lansing

Very interesting comparison.
Has anyone here had any experience with Abrasive Flow Machining, or Extrude Honing for flowing intake and heads?
Very expensive, but just a cool concept. And I would love to see how they would flow compared to out of box or hand flowed heads.

nonhog

Being it was all same day, same machine it would have been great to see a stock head in the mix.
I know there are posts with data. But the same day, same machine would have been fun to see. But take what we can get.

Thanks Mark! Very cool of you to do this.

cutlassefi

Thank you for the acknowledgement.
I have another surprise. Champion is going to flow a set of #7 SBO heads with 2.00/1.62 valves. The heads have had some bowl work done and casting/flashing addressed. They will be done on the same machine as the aluminum stuff and by the same guy. And I'm not concerned about the potential weather influence, it's still friggin hot down here.

Also the cam I did for the DX build that's getting the Edelbrock heads is as follows;
280/296 adv., 226/231@.050 on a 109 with .565/.583 lift.
As you will notice from the flow numbers, the intake plateaus at .500-.600 but the exhaust keeps climbing at those lifts. Also notice the 2 different profiles with the exhaust slower than the intake but with more lift. This cam should work well.

More to come.

drjr56

Awesome that there is someone that will take the time to do this...I know I love comparison test. Thanks for the time and effort...

cutlassefi

Maybe here's another valid reason to use aluminums over irons;

http://72.22.90.30/phpBB2/viewtopic.php?t=84866
How much time and/or money do you think the guy had in the J's, probably a bunch.

And remember the current Procomps are essentially the older style Edelbrocks.

VORTECPRO

From what I can see from my testing is: His J heads probably left a lot to be desired, a well ported production head smokes a out of the box Edelbrock or pro comp, atleast on the intake side.

cutlassefi

With all due respect, if you're comparing your recent flow numbers vs the ones I posted for the PC and Edelbrock heads, then that's like comparing apples to oranges. You can't compare 2 flow benches a half a country apart.

VORTECPRO

I have two SF 600 flow benches, both flow very close to each other, when I say close I mean within a few CFM on a 350 CFM head, also I have calibration orifaces that dont lie. I also use a Breszinski 4.155 bore adapter that does not leak. The factory G small valve head flowed 226 @ peak before it was ported, I do know I ended up with 282 CFM @ .750 lift, thats a gain of 56 CFM. When you consider the low lift flow numbers compared to my G head, the Edelbrock leaves room for improvement. Now, porting production heads aint for everyone, BUT it can be done.

cutlassefi

Geez how many people are going to care what they flow at .750 lift for crissakes?
Remember the edelbrocks are almost untouched and have a much better combustion chamber.
And until you move the port there's only so much you can do anyway.

VORTECPRO

I did have 270 @ .500, I have some pictures of a welded up chamber made into a heart shape, but my computer with the pictures is down, Ill post the pictures in the near future. Ported G head: 2.100 valve @ 28 inches, 4.155 bore. .200/158 .300/213 .400/251 .500/270 .550/274 .600/275 .700/278 .750/282.

ah64pilot

I'm no head porting pro but look at the numbers in this thread: a G head fully ported flowing 282 at an incredibly high lift and an unported Edelbrock flowing 264 at .600 lift. The G head doesn't seem like it's a better head at all. What would a fully ported Edelbrock flow? And you get the benefit of running an aluminum head? I'm trying to see the benefit of the iron head...

Like I said, I'm only looking at numbers and am not a head porting person so please educate me.

VORTECPRO

The Edelbrock head does have a lot more potential, thats a valid point. I can tell you this, if I built a 10.1 comp 455 with those ported G heads, with a hyd flattappet, I can guarantee that it would make 550 HP and look stock except for the intake, and it would run mid tens in my 3600 pound chevelle, easy.

cutlassefi

How big of a hyd flat tappet? You'd have to use something really big which would limit it's use.
When I see a build and subsequent dyno sheet then I'd be inclined to believe it, but not until then, sorry.

And notice how your flow numbers plateau after .500 lift or so, any idea why?

Steve, a fully ported Edelbrock flows about 315 at .650 or so if I'm not mistaken. That's with a 2.140 intake valve. But it reaches a plateau as well. Vortecpro, you're not getting a whole lot more than an unported Edelbrock considering you're using a larger intake valve.
I'll take an unported Edelbrock with a 2.072 intake anyday vs a ported iron with the larger 2.100, jmo.
Any idea why they all plateau at a certain point?

There's more to flow numbers than meets the eye.

VORTECPRO

I think its maxed out with out some welding, but I could be wrong. I was using the same valve shape on all the tests, but would have liked to tested some more valve shapes. I think a 2.080 valve would be a better choice. At full valve lift it did flow 298.5, retainer to guide. My 455 build is under way, so I guess we will see what kind of power is made. My friends 1980s hyd 455 build ran high 10.80s in Colorados 5800 feet physical elevation @ 3200 pounds with very primitive head work, primitive car. It was a compression engine with a tunnel ram, Engle hyd cam

VORTECPRO

you're not getting a whole lot more than an unported Edelbrock considering you're using a larger intake valve. Lets see, 25 CFM @ .200, 27 CFM @ .300 32 CFM @ .400 26 CFM @ .500, no thats not much. LOL

380 Racer

I'm no head porter, but have friends that do and they agree with Mark. They also claim Edelbrocks stall about .650 lift.

Vortecpro it seems you must have a "happy" flow bench.

cutlassefi

In my opinion Vortecpro it's not, considering the difference and the amount of work you have in them.
Plus you're at a disadvantage regarding quality of combustion chamber and your hands are more tied to a compression limit with the irons. IMO, no comparison.

Jmo

VORTECPRO

Im not familiar with the flow numbers of a stock unported G head, all I know is they flowed a peak of 226 unported, ported they flowed 282 @ .750 lift, and 298.5 with the retainer hitting the guide, any way you want to look at it they picked up a solid 56 CFM after porting. Flow benches that are calibrated with flow adapters that dont leak give pretty accurate numbers, atleast my SF 600s do.

VORTECPRO

Its allways going to be better to start with a quality aluminum aftermarket head. I just wanted to see what could be done with a production head, now I know, the amount of work was extreme to get the last bit of flow.