[jpg69bird]

Holdener dyno tested these back to back. Well, we already know the outcome.

https://www.youtube.com/watch?v=9AfeMtpi5pc

His part one video tests the Q-Jet vs some aftermarket waste of money, and the 2 bbl intake on a 400.

[GTOLou]

Always made me wonder why no one got the Chinese to make a direct clone of the factory intake - I know the ram/air intake was cloned, but that intake was too inconsistent w/ runner size, etc. I never really liked that intake. Had block off plates too - kind of a hassle.

I DO* agree w/ him, that current day and age, i really try and never use cast iron intake/heads on anything that I build or run. Just too heavy.

BTW, did he ever compare HP w/ performer to factory intake after he changed the jets.??

[Cliff R]

It wouldn't matter, the Performer is pretty restrictive on a powerful Pontiac engine. I've tested (or attempted to test) that intake on several occasions and it's a turd, especially on a 455 with decent flowing heads and moderate cam in it........

[Formulajones]

Nothing wrong with the aftermarket OEM aluminum pieces. I've tested that theory against the original iron piece and found they perform exactly the same on a mild 360-370hp-ish combo. There just isn't enough difference between them to matter at this HP level.
The best part about them is you have a separate heat cross over keeping most of that mess out of the intake itself and all that stuff is reproduced as well, you don't need the block off plates.

Since Richard would really rather have aluminum, someone should suggest to him to pick one of those up and test it on that engine for everyone to see. It'll never happen of course but this is the perfect opportunity to put all the negative theories to rest.

What I found most interesting about the test is sticking that Holley carb on there with one of those awful looking adapters and it didn't make a damn bit of difference at all. Just looking at the entry that carb had to make with most of it hitting a wall with a closed off 4 hole intake is enough to scare most people. Yet it was the same.... Proves that theory has no basis either. That engine at that power level just doesn't care.

[Cliff R]

I dyno tested the 1971 HO "re-pop" intake. As badly as they are cast for runner alignment it wasn't too far off my iron intake.

The test engine was a 428 bored to 440cid, KRE aluminum heads at 260cfm, 236/242 HR cam, 10.6 to 1 compression.

I used my own 1977 Pontiac q-jet for all the testing and also tested a Performer RPM.

The iron intake made 497hp, the RPM 491hp and the HO intake made 487hp. Never tried any intake testing with mild 400's but I'll bet the HO intake doesn't give up anything to an iron one.....

[Formulajones]

I could see maybe some sort of difference on a 500hp build, but even 10 isn't a whole bunch to get worried about, and I'd bet it could be improved upon if you wanted to spend just a little time on that OEM aluminum piece. Especially if you wanted to modify it like you modify your iron setup.

I made 507hp and 571tq on a 455 build I did a while back with the stock OEM aluminum intake and with the stock exhaust manifolds, and the factory 7F6 round port iron heads. It was nothing exotic. Good port work on the heads and a smallish 239 @ .050 hydraulic roller.


On a build like this stock 400, I don't see a big change. I tested the intake on what is basically the same engine, my RAIII 400 and the car runs identical down to the tenth and same mph. It showed no disadvantage but I did gain the separate heat cross over which is what I was really after, to see how that did on day to day driving with the crappy fuel and heat soak. That was a win and I still got to keep the divorce choke operational.

[Skip Fix]

Originally Posted by Formulajones

Nothing wrong with the aftermarket OEM aluminum pieces. I've tested that theory against the original iron piece and found they perform exactly the same on a mild 360-370hp-ish combo. There just isn't enough difference between them to matter at this HP level.
The best part about them is you have a separate heat cross over keeping most of that mess out of the intake itself and all that stuff is reproduced as well, you don't need the block off plates.

Since Richard would really rather have aluminum, someone should suggest to him to pick one of those up and test it on that engine for everyone to see. It'll never happen of course but this is the perfect opportunity to put all the negative theories to rest.

What I found most interesting about the test is sticking that Holley carb on there with one of those awful looking adapters and it didn't make a damn bit of difference at all. Just looking at the entry that carb had to make with most of it hitting a wall with a closed off 4 hole intake is enough to scare most people. Yet it was the same.... Proves that theory has no basis either. That engine at that power level just doesn't care.

When I built my first 455 with RAIV heads my machinist had raced Pontiacs had a flow bench. Got Performer as Edelbrock swore it flowed better than a factory intake- after testing it he told me to send it back not as much flow as my cleaned up 72 HO intake!

As far as adapters for a Holley on a Qjet manifold I had the HO intake on my first E head roller 455 to keep the Shaker until I modified a Shaker base for a Holley. At the track swapped a Carb Shop tweaked 73 SD Qjet for a Demon 850 on an adapter at the track and it ran .2-.3 seconds faster!

[Formulajones]

Originally Posted by Skip Fix

When I built my first 455 with RAIV heads my machinist had raced Pontiacs had a flow bench. Got Performer as Edelbrock swore it flowed better than a factory intake- after testing it he told me to send it back not as much flow as my cleaned up 72 HO intake!

As far as adapters for a Holley on a Qjet manifold I had the HO intake on my first E head roller 455 to keep the Shaker until I modified a Shaker base for a Holley. At the track swapped a Carb Shop tweaked 73 SD Qjet for a Demon 850 on an adapter at the track and it ran .2-.3 seconds faster!

Isn't that hilarious? For as bad as those adapters look you wouldn't think that would be the outcome, but somehow they seem to work.

[Cliff R]

The open adapter is a LOT better than the four hole variety. Look at the miss-match where a 4 hole would bolt against the factory iron intake and tell me it's not hurting anything.

[Cliff R]

"I'd bet it could be improved upon if you wanted to spend just a little time on that OEM aluminum piece."

The HO re-pop I dyno tested was port matched (best as I could because they hae a HORRIBLE miss-alignment with the factory intake gaskets and it was opened up under the carb to the same dimensions as my OEM HO intake shown below. So the 10hp difference much be in the runners and plenum height differences......

[Formulajones]

Originally Posted by Cliff R

The open adapter is a LOT better than the four hole variety. Look at the miss-match where a 4 hole would bolt against the factory iron intake and tell me it's not hurting anything.

That's just funny to me. Even with a proper adapter the air and fuel still has to make that turn which seems really restrictive.

I have one of those adapters around here somewhere, and I seem to remember it's only a 1/2" tall. So the turn to the intake ports from the carb base has to be pretty abrupt with nothing there in that space to help it. A lot of flat area there in the way too, seems like turbulence would be an issue.

Yet we have dyno and track runs of people using these things with no ill effect. And still people want to worry about some mild port alignment issues on an intake manifold Truth be told most of the OEM stuff is the same way, even on the iron pieces. Where do they think the mold for the repop stuff came from? People either forget that or choose to ignore it.

[Formulajones]

Originally Posted by Cliff R

"I'd bet it could be improved upon if you wanted to spend just a little time on that OEM aluminum piece."

The HO re-pop I dyno tested was port matched (best as I could because they hae a HORRIBLE miss-alignment with the factory intake gaskets and it was opened up under the carb to the same dimensions as my OEM HO intake shown below. So the 10hp difference much be in the runners and plenum height differences......

I was told plenum height was different to make room for the heat cross over but when I measured mine I couldn't find a discernable difference between that and my iron piece. Maybe slightly smaller runner size? I didn't CC those.

If that's the case, the problem should show up in air flow as you get to the bigger HP engines with more airflow demand. In theory anyway...

[Formulas]

if you look at the top of intake port to carb base heights the q'jet Pontiac intake is alot better than some GM offerings, Its sort of a medium rise intake
some OE. GM. intakes the carb base is alot closer in height in relaton to top of intake port

we have some design limitations but i believe Pontiac engineers stepped out a bit on the q'jet intake, not earth shaking but more than minimum

[Cliff R]

It ran within 4hp of the RPM so I wouldn't worry about it for a micro-second on any Pontiac build sub-500hp or so, you're just not giving up anything. The benefits of the stock intake for outweigh anything you'll find with the taller RPM. Those often take some "cobbling" to install as it moves everything up just over 1". I've had to spacer throttle brackets, no way to use any type of factory divorced or "hot-air" choke, and FORGET using the RPM with a Shaker set-up without some additional effort there.....

[Steve C.]

Results will always be combination specific.

This testing by Dave Bisschop

CNC machined plenum factory iron intake
527 HP at 5300 rpm
579 TQ at 4100 rpm

Performer RPM intake
541 HP at 5400 rpm
591 TQ at 4000 rpm

http://www.sdperformance.com/newsStory.php?newsID=44

.

[Cliff R]

And we don't race dyno's either.

I've taken ALL of the intakes mentioned at one time or another and drag strip tested them. Did additional testing with and without spacers on them two. I also tested 4 different kinds of spacers back to back.

Remarkably with the intake testing the fastest intake was the Tomahawk with a very well blended 1" open spacer and my custom tuned Holley 4781-2 850DP carb on it. It was nearly 2mph faster in MPH than all other intake/carb/spacer combinations.

It did not however win the ET contest. It gave up just enough ET and short times that the "modified" iron intake with no spacer at all bested it out by a couple hundreds of a second even though the car ran almost 2mph slower. So tit for tat with these things and some parts simply shift power or push it higher in the RPM range.

With most street driven cars with moderate gearing/converter this may not always produce the best ET compared to parts that make more low end power, plus hit the converter harder and make a lot of average power over a broad RPM range.

In closing I'd add that testing these sort of parts has always been lessons in humility. NEVER evaluate any of it by street or "seat of the pants" assessments. Parts that shove a lot of power upstairs and make more of it ALWAYS "feel" stronger on the street, but not one single time to date have they shown any big improvements at the track over the parts replaced and more times that not didn't run as quick in ET........FWIW......

[66sprint6]

Don't they go with the Performer RPM manifold for the big horsepower anyway? There's one on my Round Port engine and it looks much different.

[Cliff R]

Even the RPM has it's limitations for "big" power.

I've had customers attempt to use them on really high HP stuff only to experience distribution issues and resulting engine troubles. One customer in particular ran one on a 455 in a low 10 second application. After several times spinning the same rod bearing he went to a Tomahawk intake with a 2" spacer. Going from memory here, there is one runner on the RPM that gets crunched down a bit where another lays over it, but at the moment I don't have one in front of me to look at.

Anyhow, his intake swap immediately stopped the rod bearing issues. His engine dyno'd around 735hp at that time. The heads were 330cfm older Edelbrock round ports, so when moving that much air it's just makes more sense to use a bigger intake with straighter runners and a common plenum area vs a dual plane with a all different length runners and a divider in it..........

[ponchonlefty]

i'm wondering if the performer was a compromise. do you think it was more for economy? i just thought maybe edelbrock was targeting low compression low performance engines. trying to boost power and economy?

[PONTIAC LARRY]

My thoughts on the great oem 67+ iron Qjet is that it was based off the single 4v 63 SD Nascar intake am I right ? My 455 with ported #16 iron heads ported/ plenum modded 69 iron intake my 77 TA Qjet have ran very well , easily good for over 500 HP