[nashville beth]

I am building a 489 stroker with a ZZ502 cam (224/234 @ .527/.540" lift) and Edelbrock heads.

I have two intakes : a factory cast iron quadrajet intake (3883948) found on 1967 427/390 hp Corvettes and 325 hp Chevelles.
The competing intake is an Edelbrock Performer RPM.
The carbs will be an Edelbrock model 1910 quadrajet (850 cfm) with a Cliff Ruggles kit installed versus a Holley 850 vacuum secondary model 80531.

I took some pics to compare the height of the manifolds. Surely the Performer RPM (same height as the air-gap) is a lot taller than this quadrajet intake ?
It's not ! The Performer RPM looked to be about 1/4" taller when I placed both carb mounting pads down on the workbench and measured the height.

This should be an interesting shootout.
Vortecpro recently did a dyno run with this quadrajet cast-iron intake and posted impressive results.
495 hp with a small flat-tappet cam : 427

I think this 489 will produce 500-525 hp.
Which intake/carb combo will take the win ?

 

[dragginwagon406]

I am building a 489 stroker with a ZZ502 cam (224/234 @ .527/.540" lift) and Edelbrock heads.

I have two intakes : a factory cast iron quadrajet intake (3883948) found on 1967 427/390 hp Corvettes and 325 hp Chevelles.
The competing intake is an Edelbrock Performer RPM.
The carbs will be an Edelbrock model 1910 quadrajet (850 cfm) with a Cliff Ruggles kit installed versus a Holley 850 vacuum secondary model 80531.

I took some pics to compare the height of the manifolds. Surely the Performer RPM (same height as the air-gap) is a lot taller than this quadrajet intake ?
It's not ! The Performer RPM looked to be about 1/4" taller when I placed both carb mounting pads down on the workbench and measured the height.

View attachment 715889


View attachment 715890


This should be an interesting shootout.
Vortecpro recently did a dyno run with this quadrajet cast-iron intake and posted impressive results.
495 hp with a small flat-tappet cam : 427

I think this 489 will produce 500-525 hp.
Which intake/carb combo will take the win ?

Great info on the heights, I have the CI intake too.

 

[artmalibu]

Im no expert, but I would bet the RPM will be better. Does the Q-jet manifold will need an adaptor?

The weight difference alone would make it better imo...

 

[nashville beth]

Im no expert, but I would bet the RPM will be better. Does the Q-jet manifold will need an adaptor?

The weight difference alone would make it better imo...

No adapter is needed but a 4 hole spacer will help the quadrajet. The spacer will be as high as the hood clearance permits.
The 20 lb weight difference is meaningless IMHO.
The quadrajet should give better overall torque and the Holley better top end; but the 1910 quadrajet is 850 cfm , so it should hang in there.

 

[68Chevele]

The RPM will beat the factory intake for sure both stock for stock. If you modify the plenum on the Q-jet it might be pretty close but then there is the weight issue of the cast iron intake.

 

[Aml383]

The RPM will beat the factory intake for sure both stock for stock. If you modify the plenum on the Q-jet it might be pretty close but then there is the weight issue of the cast iron intake.

X2

 

[Malibu ss 64]

The RPM will make most hp, 20-30 more I think if the 850 va works ok. Personally would go with a 950 hp instead of that 850 va.

Why not a iron intake vs 7164 intake test? Same carb different intake. Performer RPM Big Block Chevy Oval Port Q-Jet Intake Manifold

 

[shovelrick]

RPM & the Holley carb will make the most power on a dyno I'd think, for street driving it probably wont be a noticeable difference, Quadrajet might be a little peppier in low rpm's and better mpg, and on your build I'd be surprised if either combo didn't make at least 525 hp, are you going to dyno test each combo?

 

[68Chevele]

The RPM will make most hp, 20-30 more I think if the 850 va works ok. Personally would go with a 950 hp instead of that 850 va.

Why not a iron intake vs 7164 intake test? Same carb different intake. Performer RPM Big Block Chevy Oval Port Q-Jet Intake Manifold

950hp's suffer from some booster placement issues as I was reading on some other sites.

 

[nashville beth]

RPM & the Holley carb will make the most power on a dyno I'd think, for street driving it probably wont be a noticeable difference, Quadrajet might be a little peppier in low rpm's and better mpg, and on your build I'd be surprised if either combo didn't make at least 525 hp, are you going to dyno test each combo?

I don't have access to a dyno but plan on doing acceleration tests on the track or interstate. Maybe 30 mph to 110 ? Watch out for Smokey.

 

[nashville beth]

The RPM will make most hp, 20-30 more I think if the 850 va works ok. Personally would go with a 950 hp instead of that 850 va.

Why not a iron intake vs 7164 intake test? Same carb different intake. Performer RPM Big Block Chevy Oval Port Q-Jet Intake Manifold

That would be interesting to compare all 3 intakes. If someone has one lying around they want me to put it to the test ?

 

[Malibu ss 64]

950hp's suffer from some booster placement issues as I was reading on some other sites.

Maybe a custom built 950 from Pro system or jmarkaudio?
My Pro system 1000hp works pretty good but a 1000hp might be on the big side for op, it works much better than both a 870 va and 4781 Holley I tried on same engine. 3310 was second best after the 1000hp but not same throttle response and maybe 30-40 hp down just like the 4781 and 870 va.

 

[600renegade]

Engine Masters did an intake shootout that could provide some insight as to which intake would provide the most power.

My own opinion will be the RPM intake would be hands down better performance-wise than the Q-Jet cast iron unit.... not to mention you shave 25# of ugly weight off the front of the car....

 

[jeff swisher]

I don't have access to a dyno but plan on doing acceleration tests on the track or interstate. Maybe 30 mph to 110

So we just will find out how well your butt meter works.
It is not going to be on a dyno?

I did a wheel HP dyno test back to back with a mild 350" 280H comp cam ported 601 heads 10.76 compression.
Worked over Q jet and a 750 square bore carb. Q jet Marien intake Q jet car intake plenum ported and Performer RPM intake.
The square bore made 10 more HP on the square bore intake and 10 less on the Q jet spread bore intakes.

The marine Qjet iron intake was factory stock and has the plenum at the runners cast so it is rounded instead of machined sharp like your above Q jet intake.

The automotive Qjet iron intake had the plenum removed and just a small short 1/2" divider left..so an open plenum basically.
RPM intake was 30Hp more than the Marine Q jet and only 10 more than the Q jet with opened up plenum and blended into the runners.

I did not open the runners anywhere else.
1/2" Adapters were used HP was wheel HP.

I did swap an early BBC intake like you have onto a later 450 that had the flat intake and it picked up power everywhere.
I never did any dyno testing on it.
Just a tow truck that needed more power.

 

[68Chevele]

Maybe a custom built 950 from Pro system or jmarkaudio?
My Pro system 1000hp works pretty good but a 1000hp might be on the big side for op, it works much better than both a 870 va and 4781 Holley I tried on same engine. 3310 was second best after the 1000hp but not same throttle response and maybe 30-40 hp down just like the 4781 and 870 va.

Yes sir, Mark can make it work.

 

[nashville beth]

So we just will find out how well your butt meter works.
It is not going to be on a dyno?

There are some GPS drag race apps for the phone that may do a good job of timing 1/8 or 1/4 mile.
If anyone can recommend something ?

 

[The Camaro Guy]

I switched the GM 427 intake 3866948 for the Air Gap using the same 750 Holley VA. Could not tell any difference on my 468, bet my mechanic the AG would make a difference. . . .cost 12 pack

 

[68Chevele]

I should get one of those old cart intake at the swaps this year and work one over for a test some day. Would be fun welding one and making something else work great.

 

[72BB Nova]

There are some GPS drag race apps for the phone that may do a good job of timing 1/8 or 1/4 mile.
If anyone can recommend something ?

Dragy Motorsports, A fun little toy that seems to work pretty good

 

[nashville beth]

Did many of you see Mark (vortecpro) post 495 hp with this cast iron quadrajet intake with a small cam ?
I'm not so sure the Performer RPM will beat that factory "boat anchor" intake by much : 427