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#982670 - 09/09/13 09:54 AM Performer Rpm, spacer, and a stock hood.
breakneck88 Offline
Member

Registered: 07/18/12
Posts: 147
Loc: lehigh Valley pa
I have done a billion searches and I can't come up with a definitive answer if a performer rpm, 1" adapter/spacer, and a stock hood will play well together. I have vortec heads and I am using a quadrajet so I'm pretty limited in manifold selection. Motor is a 425 hp 383 that will be seeing a 150 shot on track days. Has anyone run the same intake /spacer/quadrajet combo? If so, how was it? I wanted to use a dual snorkel set up from a camaro but I don't want to commit $ if it won't fit. Any ideas? Any help would be greatly appreciated.

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#982677 - 09/09/13 11:15 AM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
robs 85ss Offline
10+ Year
Member

Registered: 11/23/01
Posts: 1303
Loc: pa
It will be VERY close if it will work all all with a drop base 14x3. I ran an rpm airgap intake with no spacer and it was close. I may have ran a small air cleaner spacer though to clear choke linkage. Either way it would be VERY close. You could probably get away with one of those triangular edelbrock foam aircleaners if you had to.

http://www.jegs.com/i/Edelbrock/350/1002/10002/-1
_________________________
1985 Monte Carlo SS
Vortec headed 357 smile
Muncie m20 4 speed.

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#982682 - 09/09/13 12:05 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
200kSS Offline
10+ Year
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Registered: 07/02/00
Posts: 2502
Loc: Southeast Missouri
Run a Performer or the GM intake. Still dual plane, the Q-jet will bolt up without an adapter and still have room for the nitrous plate and a real air cleaner.
_________________________
88 SS black/maroon. Trophy case is full...time to DRIVE it.
80 Malibu 2dr, 406/TH350/GN 8.5 rear. MPG=low. Smiles per mile=HIGH.

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#982700 - 09/09/13 03:05 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
MAP Offline
10+ Year
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Registered: 05/11/02
Posts: 3567
Loc: Yuma, AZ
Hi BN88,

I think robs' 85ss is quite right. No matter what, the top of the carb will be so close to the underside of the hood, that any benefit you get from the spacer, could easily get cancelled by the restricted airflow curtain area (from restricted height) in the air cleaner element right above the perimeter of the carburetor neck - that is, the usual air cleaner flow "choke point" when dealing with this type of problem.

If you want the best of both worlds while keeping the hood modification to a bare minimum, then maybe adding a scoop that's very roughly 18" square would get the job done if that's acceptable to you. Plus, you might be able to duct some fresh, cool air into the engine this way.

Best,
MAP


Edited by MAP (09/09/13 03:07 PM)

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#982705 - 09/09/13 03:29 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
breakneck88 Offline
Member

Registered: 07/18/12
Posts: 147
Loc: lehigh Valley pa
I like the idea of adding a scoop. I will look into that as well. I guess I can return the rpm to Jegs and have it replaced with the plain performer. Now to find bolt on scoops. I guess I will have to cut the bracing. I wonder if that is a bad idea?

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#982710 - 09/09/13 04:28 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
MAP Offline
10+ Year
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Registered: 05/11/02
Posts: 3567
Loc: Yuma, AZ
Hi Breakneck,

I'm confused - if you dial-back to the base Performer series, then why even bother with a spacer or a hood scoop? The Performer RPM series is really an outstanding design (albeit copied ad infinitum these days,) that merits the effort to optimize the rest of the intake system to the extent of even thinking about cutting the hood for a scoop.

The base Performer, although no slouch by any means, doesn't, in my opinion. Spacers help top-end output, and the base Performer is a low-rpm piece.

On Edit: for the Performer RPM, I presume you mean a four-barrel spacer, or at least a spacer that preserves the dual-plane plenum division. If an open spacer, then you should probably switch to an open-plenum manifold.

Best,
MAP


Edited by MAP (09/09/13 06:27 PM)

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#982717 - 09/09/13 06:33 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5495
Loc: Toledo, Ohio
.. I think the 'spacer' he mentions is the nitrous plate... you would prolly need a 2" high drop base aircleaner to use the Performer RPM intake manifold and plate... a 2" high K&N filter element would prolly flow enough air if one is available... need at least 3/4" from carb. top to underside of air filter lid to avoid 'choking' the carb./restricting air flow...

.. I have a 4" high element in a drop base air cleaner assembly with stock intake manifold/no spacer and the wingnut on top just rubs the under hood insulation...

.. I think RPM intakes are 3/4" - 1" higher than stock... is the nitrous plate a full inch high?

.. 14" diameter air cleaner elements flow about 1,000 CFM for each inch of height... (I don't know how many inches of mercury (vacuum) they tested that at) . K&N's flow a little more than the pleated paper elements... Obviously, you go with taller elements IF you have the room... some old pickup trucks allowed 6" and/or stacking a couple of 4" elements... which also give more resistance to dust/dirt clogging in offroad dirt track/road usage...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#982751 - 09/09/13 11:50 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
200kSS Offline
10+ Year
Member

Registered: 07/02/00
Posts: 2502
Loc: Southeast Missouri
The spacer he's referring to is the adapter from squarebore intake (performer RPM) to spreadbore carb, aka Quadrajet. These spacers are approx. 1inch tall IIRC. Add another 1/2 inch of nitrous plate (plus gaskets on top and bottom of each) and I'm not sure how you'll get adequate air cleaner clearance with a stock hood. Drop base air cleaners are great, but what is that magic spec for top of air horn on the carb to bottom of the air cleaner lid.... 1/2inch to 1 inch minimum?

Every G-body in our fleet has a cowl hood so I can't get any real measurements.
_________________________
88 SS black/maroon. Trophy case is full...time to DRIVE it.
80 Malibu 2dr, 406/TH350/GN 8.5 rear. MPG=low. Smiles per mile=HIGH.

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#982782 - 09/10/13 01:10 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5495
Loc: Toledo, Ohio
. Oh, I thought the Performer RPM AirGap was available in a Q-Jet carb. spreadbore version...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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#982783 - 09/10/13 01:10 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
BadSS Offline
10+ Year
Member

Registered: 05/30/00
Posts: 1218
Loc: Pearl, MS, 39208
If you can find it,,, the Wieand 7525 single plane (no longer produced) was my favorite low rise single plane intake - especially for larger engines. They still pop up every now and again. It will accept a quad (or Holley) and I had double stacked nitrous plates with a 3" drop filter that would barely rub the stock hood under engine torque - I used a limiter to stop the engine "flex" and it worked like a charm.

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#982784 - 09/10/13 01:18 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
88ss408 Online   content
Member

Registered: 08/13/07
Posts: 1320
Loc: miramichi,new-brunswick
the performer air-gap is for the Q-jet the performer RPM air-gap is not.the part numbers are 2601 and 7501 i think.
_________________________
1988 monte carlo ss 408 sbc 11:1 compression a.f.r.195cc heads accel ignition system comp cams .507/.510 air gap intake 800cfm edelbrock carb th350 trans 3000 stall torque headman headers 3" dual super 40's 3.73:1 limited slip
-----------------------------------------------------
1984 monte carlo cs 400,headers,th250c,air gap intake

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#982787 - 09/10/13 01:27 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
200kSS Offline
10+ Year
Member

Registered: 07/02/00
Posts: 2502
Loc: Southeast Missouri
Unfortunately the p/n's listed won't fit his VORTEC heads.

Edelbrock p/n 2116 will be the Performer intake for vortecs. The only other vortec intake that will allow a Q-jet to bolt up without an adapter is the GM p/n 12496820, which has gone up in price in the last 10 years.

http://www.summitracing.com/parts/nal-12496820

If you're ok with adding a hood scoop any any type, I'd recommend swapping to a cowl induction style hood.


Edited by 200kSS (09/10/13 01:29 PM)
_________________________
88 SS black/maroon. Trophy case is full...time to DRIVE it.
80 Malibu 2dr, 406/TH350/GN 8.5 rear. MPG=low. Smiles per mile=HIGH.

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#982792 - 09/10/13 02:02 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
MAP Offline
10+ Year
Member

Registered: 05/11/02
Posts: 3567
Loc: Yuma, AZ
Hi Folks,

I thought I was wrong after Buzz's post, but after reading and then re-reading the OP's comments a couple of times, I think I got the full sense of it.

Question: I remember seeing Q-jet adapters back in the day that were much thinner than 1". Maybe he can get/make one of those? Or, if the Q-jet secondaries are too big to open into the RPM plenum without a thick spacer, then take a carbide burr and create relief scallops in the RPM plenum to permit such? There's plenty of meat in the plenum sidewalls as a I recall.

I admit that the most appealing option would be to work with the hood to afford more height for the motor, as 200kSS said.

Best,
MAP


Edited by MAP (09/10/13 02:06 PM)

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#982799 - 09/10/13 04:06 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
breakneck88 Offline
Member

Registered: 07/18/12
Posts: 147
Loc: lehigh Valley pa
Yup you guys nailed it. Sorry if I was a little hard to follow. My set up is a ccc with a custom chip burned. And vortec heads on a 383. The vortec heads are what has me all messed up. There are hardly any manifold out there for a quadrajet. So in order to use a Rpm manifold I had to add the adapter. Then when I use the nitrous plate I will be well into the hood. So I sent back the RPM manifold to be replaced by the plain Performer manifold. So now I have a nice new 4 hole adapter for sale or I might try it as a spacer if it fits. I wish I had the money for a cowl hood but right now I'm trying to finish the motor build, transmission build, exhaust build, and fuel system. I bit of a little more than I should have.

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#982800 - 09/10/13 04:07 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
breakneck88 Offline
Member

Registered: 07/18/12
Posts: 147
Loc: lehigh Valley pa
The performer vortec manifold is dual pattern for square and spread and it's naturally lower

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#982802 - 09/10/13 04:16 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
88ss408 Online   content
Member

Registered: 08/13/07
Posts: 1320
Loc: miramichi,new-brunswick
yeah a performer will fit your build better. low rise dual pattern carb flange.
_________________________
1988 monte carlo ss 408 sbc 11:1 compression a.f.r.195cc heads accel ignition system comp cams .507/.510 air gap intake 800cfm edelbrock carb th350 trans 3000 stall torque headman headers 3" dual super 40's 3.73:1 limited slip
-----------------------------------------------------
1984 monte carlo cs 400,headers,th250c,air gap intake

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#982863 - 09/11/13 04:36 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
BadSS Offline
10+ Year
Member

Registered: 05/30/00
Posts: 1218
Loc: Pearl, MS, 39208
Yep. I didn't catch the Vortecs. Seems as popular a swap as those heads are you would think they would have more Qjet options.

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#983388 - 09/17/13 02:32 PM Re: Performer Rpm, spacer, and a stock hood. [Re: breakneck88]
BuzzLOL Offline
Member

Registered: 05/02/06
Posts: 5495
Loc: Toledo, Ohio
. Yeah, something like 99% of Ford 351W's came with a 2-bbl. carb., I was always amazed that Weiand didn't offer a 4-bbl. intake for it for many years...
_________________________
'86 Monte LS (total'd Fall '2013), '87 GTA TransAm TPI350 TH700-R4, '85 Fiero 5-speed, '75 MG Midget Buick Alum.V8 BW 5-speed manual, '77 Pontiac Astre Formula wagon 5-speed posi, '78 F150 4WD 351"M ==> 400" C6, '79 Caddy Seville Olds EFI 350" TH400, 19' Slickcraft 425HP 351W MerCruiser I/O

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