I've got an 84 L69....with vortec heads...Comp cam
650 Qjet and hooker headers.....

I want a decent idle vaccum, it's a daily driver, but want POWER..

I am trying to decide between the RPM Performer and the RPM Air Gap.

What's the difference between the two?


Will the RPM Air-gap sacrifice too much vaccum to be a daily driver?

Which should I buy



[This message has been edited by gruveb (edited February 10, 2001).]

 

I don't see why the RPM air gap would cause you to lose alot of vaccum. The cam has more to do with that than any other single thing. I run a vaccum resivoir because my cam is way too large to really run on the street with all of the accessories. I think I paid around $40 for it and install was simple. A small price to pay for having it the way I want.

I'm going to be changing to the RPM AG myself this spring so I'd be interested in what you think of it after you get it installed

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'87 RS 402 Big Block
'92 S-10 Blazer 4X4
'77 3/4T Chevy 4X4 P/U with 500 Cadillac
Qsac

 

I don't think the Air Gap will fit under the stock hood, the RPM on mine just barely does w/ a drop base 14x3" cleaner (wingnut rubs underside of hood)... I'm using a Holley BTW, I don't know if there is a height difference between that and your Qjet.

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Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

[This message has been edited by Ray87Z (edited February 10, 2001).]

 

Just so you know they are the same height, heck they are 99% the same, except for the fact the Air-Gap has the runners seperated. Other than that they are identical in all measurements. Performer RPM & Performer RPM Air-Gap

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White 92 RS,388 cu.in.N/A
3.73 gears,auburn posi
Best 60 ft : 1.97
Best 1/4 : 12.679
Steve Spohn
Rear Suspension
Autometer guages
Extremely Loud Stereo !
Driven Daily
HOOKER LT's SOON!!! & 4 inch Exh.

 

Slush,

What does the seperated runners affect and how?

Thanks

 

The RPM or RPM-AG, will not fit under the stock hood. I have the RPM and Edelbrock carb on my 86 Z-28. I had to install a scoop to get clearance. I instaled the scoop off a 79 Z-28, it looks preety good.

 

Slush I think you are a little miss informed! I am looking at the instructions for my RPM air gap right now. The carb mounting pad on my RPM air gap is .7 inches higher than the old RPM design and .125 inches forward. This redesign is for improved perfomance. It's also why I had to reinvent the throttle cable bracket!

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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

2001 Dodge Ram Quad Cab 5.9L 4*2

The Bowtie
ASE Certified Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

Umm, actually the RPM will fit w/ a drop base aircleaner. I'm living proof. It would not fit w/ a standard base aircleaner though.

This may have something to do w/ the Vortec heads though, I've heard others w/ different heads say the RPM won't fit too. Beats me, all I know is my combo fits just fine under the hood. Like I said the wingnut rubs the underside of the hood when the engine torques over.

Are you sure the Air Gap and RPM are the same height? I thought it was like a half inch taller. Hmm, Air Gap sounds nice then.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

[This message has been edited by Ray87Z (edited February 10, 2001).]

 

I have rpm, holley and vortec heads - fits under stock hood fine.

 

I had an RPM (sitting too high... POS) with a carter and drop base air cleaner on it, cleared the hood of my TA just fine. Too bad the manifold was junk.

 

So, which would be best, the RPM Performer or the RPM Air gap?

Provided I need to change from my stock air cleaner....glad I didn't drop the dough on a K & N filter yet.

 

The RPM Air Gap should make more power. Because the runners are separated from the rest of the manifold, it allows more air to surround the runners and cool them off. Car Craft or Chevy High Performance did a dyno test of one compared to the regular RPM and the Air Gap gained about 8hp sitting in a hot dyno room. The benefits when placed in a moving car, especially on a cool night should be even better. I have the RPM manifold, GM heads, Holley 4bbl, and the single-snorkel lg4 air cleaner. I have no clearance problems on my 82 camaro. I think the air gap is the same size, but I'm not sure.

 

Has anyone read my post!!!! Damnit the RPM Air Gap is taller than the RPM. Jeez.



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84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

2001 Dodge Ram Quad Cab 5.9L 4*2

The Bowtie
ASE Certified Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

What do you mean it's junk Madmax? Every dyno run I've seen w/ it has had pretty good results. Even compared to some of the single plane manifolds.

------------------
Ray87Z
-Vortec headed 350.
86 IROC w/ a cammed 305 TPI.
Formerly Ray86IROC.
www.inter-scape.com/Ray

 

I think one reason for the air gap was to keep hot oil off the bottom of the intake runners which inturn will keep the incomming air cooler. This is not a new idea just a new rendition of an old one.

[This message has been edited by steve8586iroc (edited February 10, 2001).]

 

The passenger side intake ports were 1/4" too high, didnt fit right. Never even torqued it down, just sent it back. I had other edelbrock problems in the past, and with all the wonderful things I hear about their TPI base here, I wont buy any more of their products or recommend them.
IMO it was a nice manifold aside from the fact there was nothing that you could bolt it up to and use it on. Kinda makes it pointless.

Oh, and CamaroMike is right... the air gap sits .2" higher in the front, and -.05" in the back. It *might* fit. I had about 1/2 or 3/4" of clearance. May vary depending on what carb and air cleaner you use as well.

[This message has been edited by madmax (edited February 10, 2001).]

 

Last I heard the RPM airgap was only offered in the square bore configuration. To run your Qjet you'll need an adapter and I seriously doubt it will fit under a stock hood. I may be wrong about that but last I checked Edelbrock didn't offer the airgap for Qjets. If they do would someone please let me know the part number so I can get one. Thanks and Good Luck

 

So the RPM Air gap doesn't accept Qjet's? Is that right?

First I heard of it......

 

I agree with madmax the intake ports are a little high but that is to straighten airflow! Just hope I don't have vacuum leaks!

------------------
84 Camaro ZZ4 with HOT cam. 1.88 60' (12.98 @ 105MPH E.T.)
Other Mods: You name it and I have probably changed it.

2001 Dodge Ram Quad Cab 5.9L 4*2

The Bowtie
ASE Certified Auto Tech
LIVE AND DIE BY THE ALMIGHTY BOWTIE!

 

I don't know about the rest of you, but I know it won't fit under my hood. I've already shoved a BBC in the car. All I want to know is the RPM AG or even the RPM a POS or does it put out the power?

 

Im sure it works good, if it fits. When I said it was too high, I mean that the ports were totally out of alignment with the bolt holes and bottom of the intake on ONE SIDE. No amount of work short of totally redoing at least 1" into the passenger side ports would have fixed it.

From edelcrock about the airgap:
"For square bore carburetors only. No provision for exhaust heated chokes and no exhaust crossover. Not for 1987 and later cast iron heads and will not fit under stock Vette hood."

The 87 and later part isnt really too much of a problem, but the square bore is. The PN is 7501 and it doesnt have an EGR port either.
Perf RPM: 7101
Perf RPM Q-jet: 7104
Perf RPM Vortec: 7116
Theres no RPM Vortec for spreadbore carbs. Neither of the squarebore only intakes look like you could modify the manifold to accept a spreadbore short of an adapter or major work.

[This message has been edited by madmax (edited February 10, 2001).]

 

Okay guys, this is my new problem. You guys are talking about the clearance issue and that is really important right now since I'm about to order the parts within the week. First off it's the 330hp crate engine with vortec heads. I wanted to get the rpm air gap just because of the future when I swap cams and make 380hp and 415 ft-lbs. Anyways, you guys talk about the drop base air cleaner. My BIG problem is that I'm using the holley 670cfm TB and a 1/2" adaptor plate. I have the 5.0ho dual snorkel drop base air cleaner right now. Is that all the drop I need or what? Please Please help me, just give me an air cleaner that'll drop it low enough to fit under the stock hood.
One more thing. Is that 1000cfm edelbrock triangle looking air filter an option. It woudl be temporary. I'll be getting the ss hood this summer so then I could go to a normal air cleaner.
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, Jon (91 RS too many mods to list), getting new engine in summer

[This message has been edited by JPrevost (edited February 11, 2001).]

 

ok my question? if you have either of the 2 on your car and you fllor it from a dead stop will it go good or is there lag untill you hit 1500 rpm??

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1989 firebird formula

Mods: converted from T.B.I. to a carburator 305 to a 350. Flowmater exhaust,hedman shortie hedders,202 160 (882) heads,.447/.447 lift 222@.050 duration speed pro 327/350hp cam 350 .40 over (356) Edlebrock torker2 and a 600 edlebrock manual choke (1405)

Future mods performer rpm air gap intake (polished) comp roller cam, and way better headsa 400 defintely in the works!

 

Perhaps the reason people are having trouble with the RPM Air gap lining up with thier vortec heads is because the heads have been milled to maintain the proper compression for a 305, but they neglected to mill the intake to match......

 

RPM Air-Gap (non-EGR) #7501*
According to edelbroc:

Carburetor Recommendations: Performer #1407 (750 cfm) - Ref. A, I, K, 0

Installation Notes: Use #8504 Edelbrock bolt kit. Recommended intake gasket: Fel-Pro #1205.
Manifold height: A-4.20", B-5.25" (same as #7101), see manifold selection page.


Same height as the 7101, which is the Performer RPM manifold.

 

MADMAX,

I read what Edelbrock said about the RPM Air-Gap, #7501....but they do make # 7516, which is for Vortec heads......

More than likely, it takes the same Carb, and if I want this intake, and I do, I'll have to get a different carb......

I'm going to email them since it's not on their web site and ask....

Let you know what they say.

 

i'm with max on the edlebrock quality issue. few years back they were about the only place to get intakes, but not anymore. for a dual plane i like the weiland stealth. never really had anything to run a single plane on. i put a rpm preformer w/holley carb on a 355 and it cleared the hood ok.

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ICON Motorsports

1st & 3rd