[Badbird69]

A few months ago, amid the ongoing controversy of CV-1 versus Edelbrock wideports, we agreed with Roland Racing to do some independent testing. As I stated before, Jim Sammons did not ask for a blind endorsement - he asked for an honest evaluation. Most objective people realize that somewhere between all of the hype and all the bashing, lies the truth.

We decided to do back-to-back dyno tests using our stock block 475 motor. We did our best to make this a fair comparison using the same short block, headers, carb, rocker arm ratios and equal compression ratios.

The Edelbrock heads have obviously been ported into the wideport configuration and are fitted with titanium valves. The intake is a ported Victor. The CV-1 heads had some bowl blending, but otherwise untouched "as cast" ports. They were supplied with standard issue stainless valves. The intake was ported and gasket matched locally. Both valve trains consisted of Manley springs, T&D 1.7 ratio shaft rockers, 3/8" pushrods and Crower rollers.

The shortblock is a filled 455 block, billet main caps, lifter bore braces, 4.22 bore, 4.25 stroke, forged crank, aluminum rods, gas ported pistons, light ring package, custom roller cam (lobe .445, .440, duration 276, 284) standard firing order, good oil pan, crank trigger, dry decked, 11:1 compression. Accessory pieces include an external water pump, stepped headers, vacuum pump and a Shaker prepped 1150 carb. Nothing too exotic here.

No jetting changes were made to either combo. Because the CV-1 heads were new to us, we moved the timing around to see what it liked. That's it. We simply warmed the motor up, adjusted the valves and made some pulls.

Our dyno pulls were from 5500 rpm to 7700 rpm, with a test range of 5500-7500 for average torque and horsepower comparisons. Those who have been to the dyno know that there are raw numbers and corrected numbers. Corrected numbers are calculated to correct the raw numbers to what they would be at sea level. Many race teams only look at the raw numbers, as the correction factor is not always dependable. Raw numbers are rarely as high as corrected numbers and are therefore not nearly as exciting, but they are real. For the sake of comparison, we will show the average raw numbers. For the sake of interest, we will show the corrected peak horsepower numbers.

Again, the test range was from 5500 rpm to 7500 rpm.

Raw average torque and horsepower for the wideport E heads were 539.8 and 659.8 respectively. Peak corrected horsepower was 781.0 @ 7100 rpm.

Raw average torque and horsepower for the CV-1 heads were 562.8 and 694.3 respectively. Peak corrected horsepower was 815.7 @ 7000 rpm. It was still making 805.8 horsepower @ 7500 rpm

I think all of our jaws dropped when we saw the raw numbers come up. Seeing a set of unported street heads outperform our ported race heads was impressive, to say the least.

Clearly, this test will not put to rest all of the doubts, but it certainly shows great potential. Just think what they will do with a little port work. If time allows, we will test this motor in the car this fall.

Dick Fulton

[T Syron]

Nice comparison. Here come the haters.

Tom Syron

[S/st 54]

That's pretty cool! Congrats on both! I know you spent Some time doing all that it's kinda rewarding seeing and answering your own questions.

I hope you have the same such luck that I had with the track numbers!Either way I wish ya the best!

[mike leech]

very nice write up! good job on keeping it as fair as possible as well. And kudos are in order for the cv1 "gang". As i have stated before the heads obviously have potential....and this looks to be a fair comparison. Question...Same cam and headers?

I said i would be the first to say good job, and i am. Good job!

[mike leech]

dang it! i'm third!

[GTO Dan]

Great test methodology and nice back to back. Interesting to see how they perform on the track in back to back.

Those CV 1 certainly showed the strength on that stock bore, wonder if any difference using an aftermarket large bore.

Congrats to the CV 1 folks and to you for the impressive results.

[David Holmberg]

Great test and results.

Now get to the track and lower that record.

[john marcella]

Originally Posted by Badbird69

A few months ago, amid the ongoing controversy of CV-1 versus Edelbrock wideports, we agreed with Roland Racing to do some independent testing. As I stated before, Jim Sammons did not ask for a blind endorsement - he asked for an honest evaluation. Most objective people realize that somewhere between all of the hype and all the bashing, lies the truth.

We decided to do back-to-back dyno tests using our stock block 475 motor. We did our best to make this a fair comparison using the same short block, headers, carb, rocker arm ratios and equal compression ratios.

The Edelbrock heads have obviously been ported into the wideport configuration and are fitted with titanium valves. The intake is a ported Victor. The CV-1 heads had some bowl blending, but otherwise untouched "as cast" ports. They were supplied with standard issue stainless valves. The intake was ported and gasket matched locally. Both valve trains consisted of Manley springs, T&D 1.7 ratio shaft rockers, 3/8" pushrods and Crower rollers.

The shortblock is a filled 455 block, billet main caps, lifter bore braces, 4.22 bore, 4.25 stroke, forged crank, aluminum rods, gas ported pistons, light ring package, custom roller cam (lobe .445, .440, duration 276, 284) standard firing order, good oil pan, crank trigger, dry decked, 11:1 compression. Accessory pieces include an external water pump, stepped headers, vacuum pump and a Shaker prepped 1150 carb. Nothing too exotic here.

No jetting changes were made to either combo. Because the CV-1 heads were new to us, we moved the timing around to see what it liked. That's it. We simply warmed the motor up, adjusted the valves and made some pulls.

Our dyno pulls were from 5500 rpm to 7700 rpm, with a test range of 5500-7500 for average torque and horsepower comparisons. Those who have been to the dyno know that there are raw numbers and corrected numbers. Corrected numbers are calculated to correct the raw numbers to what they would be at sea level. Many race teams only look at the raw numbers, as the correction factor is not always dependable. Raw numbers are rarely as high as corrected numbers and are therefore not nearly as exciting, but they are real. For the sake of comparison, we will show the average raw numbers. For the sake of interest, we will show the corrected peak horsepower numbers.

Again, the test range was from 5500 rpm to 7500 rpm.

Raw average torque and horsepower for the wideport E heads were 539.8 and 659.8 respectively. Peak corrected horsepower was 781.0 @ 7100 rpm.

Raw average torque and horsepower for the CV-1 heads were 562.8 and 694.3 respectively. Peak corrected horsepower was 815.7 @ 7000 rpm. It was still making 805.8 horsepower @ 7500 rpm

I think all of our jaws dropped when we saw the raw numbers come up. Seeing a set of unported street heads outperform our ported race heads was impressive, to say the least.

Clearly, this test will not put to rest all of the doubts, but it certainly shows great potential. Just think what they will do with a little port work. If time allows, we will test this motor in the car this fall.

Dick Fulton

Did you do this for the E-head combo as well?(Timing)

Also what was the chamber volume of each set of heads? What was the fuel curve like fore each set of heads?
What was the cross section of the victor at the plenum? Stock? (don't want to be testing the manifold, just heads right?)
Why was the CV compared to a old E-head and not a High Port or PP or Tiger?

I know im on the list of Haters, but im not really.
I think the CV has its place, and have actually recommended it to people a few times with in the last year.


If the Victor Cross section at the plenum was adequate, and fuel curves were "ON" for both, and timing was "ON" for both, and camber volume was the same for both.............................................. ....Then I say CONGRATULATIONS to the CV camp , GOOD JOB!

[GTOLou]

Great stuff -

What number of pulls per each head did you do? The averages for each was based of two pulls or three pulls?

Thanks!

[steve25]

Thats just what I would expext from the CV1s with there more consitant port area over the wide ports and the CVs higher short turn, some 3/8 th inch over the wide port set up.

[WARPed]

This is great news and shows the CV-1's are doing what they were designed for in the first place - a less expensive topend/valvetrain to deliver at least as good e wide port power. One bonus using CV-1's would be you are at the starting point as far as porting goes while the wide ports are near there max & another they run cooler.
Good Job!!

[Tim Corcoran]

Too bad you couldn't have thrown a set of Tiger heads on there and see how they would compare.

[johnta1]

Congrats on the dyno tests.

Why was the CV compared to a old E-head and not a High Port or PP or Tiger?

Because of the EHTTFMF group harassing/bashing going on?

[LiL Jack]

So you compared a 350 cfm or so inline street head to a 400 cfm or so canted valve head?

Good job, I guess?

Will you run both combos on the track?

[65nss4spdGTO]

First off I want to acknowledge Dick for committing his time and resources for this test, anytime you can provide this type of information, it helps the Pontiac community moving forward.

Dick expressed interest in the CV-1 head a couple of years back, but like many guys here, was wanting to see results. We had a chance to talk about the various Pontiac heads on the market and he had a chance to see the CV-1 heads at my shop last year. He also expressed interest in the other heads as we had discussions on the HP, Tiger and the V stuff, he wants to see the Pontiac community continue to develop. At his level of racing, a BBC would fit the bill, but takes pride in the fact he is competing with the Pontiac. Like many Pontiac racers, he has used the Edelbrock heads for years achieving incredible performance and since this is his back up motor and has run the combination, it was a great platform for a comparison.

I was not involved in preparing the heads, but I did speak with Dick about the heads and how they were prepared. They are as cast runners with a competition valve job and bowl blending, no different than any other performance head that would have been provided by other Pontiac vendors. I do know Dick went to great lengths to make this test an apples to apples comparison in compression, cam and carb.

Calvin Hill
Hill Performance
708-250-7420

[65nss4spdGTO]

Originally Posted by LiL Jack

So you compared a 350 cfm or so inline street head to a 400 cfm or so canted valve head?

Good job, I guess?

Will you run both combos on the track?

So Wide Port heads only flow 350 CFM? I also don't believe the CV-1 head flowed 400 CFM.

Calvin Hill
Hill Performance
708-250-7420

[dci]

Very good data Mr Fulton and crew. These are the kind of test's and data that we can all use. Same engine, same dyno, same day. Very nice!!!! Some will criticize, some will applaud, but in the end everyone benefits. Great job !!!!!



Don Johnston
DCI MOTORSPORTS INC.
330-850-5050 shop
330-628-3354 cell
Designer of the DCI Tiger Heads and the NEW DCI Ram Air 5 Heads!!!!!!

[LiL Jack]

Originally Posted by 65nss4spdGTO

So Wide Port heads only flow 350 CFM? I also don't believe the CV-1 head flowed 400 CFM.

Calvin Hill
Hill Performance
708-250-7420

Depends on who did the wide ports. I had a set that only went 350 when they first came out.

So now it's a valve job and bowl work on the cv1s.... Nice

[BruceWilkie]

Thanks for your efforts. I'm sure you have answers to the picky questions and gave both combos a fair/honest test. I believe you used the std issue "hood clearin" street/strip single 4 intake for porting as well, not the new Race intakes in development.

Somebody is bound to try to make issue with you using shaft rockers and cost... (Personally I'd prefer shafts on any head much beyond .600"-.650" lift or significantly more aggressive than a hydraulic flat or roller. Available budget often changes our preference to alternative though. However, I wish you had tested with stud type just to show that the CV1 has a very stable stud boss and shafts arent mandatory)

I'm sure we'll hear about the "different levels" of wide ports too... so I guess all will want to see flow numbers, BSFC and such.

Basically you have taken your known combo and swapped heads/intake. And you've done it about as fair as you could. Thanks again.

Look forward to seeing in car results... I suspect you already have a good baseline of how the wideport combo works on the track.

[LiL Jack]

Originally Posted by WARPed

This is great news and shows the CV-1's are doing what they were designed for in the first place - a less expensive topend/valvetrain to deliver at least as good e wide port power. One bonus using CV-1's would be you are at the starting point as far as porting goes while the wide ports are near there max & another they run cooler.
Good Job!!

No CV1 motor can come close to a max E head.

That's the bottom line, sorry to burst your bubble.