CHPshown67

I just recently changed my intake on my 327ci 67 Camaro from a Edelbrock Performer to an RPM Air-gap, and i now have no power under 2500-3000 RPM. I stomp on it and there is a pause, like there not enough fuel, or a Vacuum leak, but then after about 3 grand it takes right off. I Took the Damn intake off and put it back on and the same problem is still there. I adjusted the carb and checked all vacuum lines, and have no idea what to do now. I am about ready to put the old intake back on. I have a Carter 625 cfm carb on there right now, and my cam isnt too aggressive. Do I need a bigger carb?? Someone help

Dirt Reynolds

The Air Gap might not give you the throttle response down low that you have become used to with the Performer. 2500 RPM and up is where the RPM intake comes into its own, wheras the Performer gives better lower RPM response but might not give as much power over 5500 as the RPM will.

Its probably more noticeable on your engine due to its smaller size than the usual 350.

Dave

CHPshown67

So am i basically screwed or is there anything i can do to increase the throttle response. There is a good 2 second pause when i get on it. I Was thinking about going to a Demon "Speed Demon" Carb any way, would that help?

Capn Pete

I think I agree with Dave on this one. My '81 had an Edelbrock Performer intake originally on it, but in my great "quest" for more power, I bought a Weiand "Stealth" intake --- a little cheaper --- but equivalent to the Performer RPM intake. It was a while ago now, but I know it seemed to pull a little harder up top, but more hesitant throttle response down low sounds familiar. At around the same time though, I also changed carbs from the stock Q-jet to a 600 vac. secondary Holley. I absolutely hated the Holley --- maybe if it were a double pumper, mechanical secondary I would have liked it, but it had terrible throttle response (especially for daily/street driving) so I switched back to the Q-jet.

Make sure you haven't changed anything except the intake before you start blaming it for your poor low-end power, but if nothing has changed, then I'd have to say it's the "nature of the beast" to a degree?

One thing I can say (although I don't want to compare apples to oranges) is that my dad has an RPM Air-Gap on his '73, and from the couple times we've driven it up and down our street (for quick test runs) it seems like it wants to make power up higher in the RPM band. HOWEVER, the car is NOT setup yet, and the cam we're using has lift around ~.500", and the duration is over 300 degrees, so I think it's intended to be a high revving cam, so I don't know that it's the intake's fault.

Bliggida

If I remember correctly, I believe Edelbrock reccomends at least a 750 CFM carb. for the Performer RPM Air-Gap. That seems like a lot of carb. for 327 but if its worked over it should be ok. I dunno if the displacement is enough to hurt you - could very well be. Edelbrock usually shows graphs of it on 350's or 400's.

Sounds like something is off. The Air Gap is made for mid and upper RPM power but, even down low it shouldn't dawg out like you're talkin' about. What about vaccuum advance, and timing. Could the springs in the dist. need adjusting now that your induction has changed.
I'm wondering if your engine is still trying to make power down low, when the parts are made to hit up higher. If the springs were matched to come in (later?) then that may relieve the pause.

Because it may accelerate slower from idle but it should never pause like that.

CHPshown67

I am currently running an MSD Pro Billet Distributor (NON-HEI) with the 2 Thick silver springs in use. Hope this information helps in figuring out the problem

Bliggida

I don't think its the intakes fault. I went back and read up on it in Edelbrock Catalog and also in Summit's. And both of them were clear to indicate the Air-Gap helped to increase mid and upper RPM performance while not sacrificing low end torque. And that it was a 1,500 to 6,500 intake.

The Torker II was rated at 2,500 to 6,500+. So why your Air Gap is acting bigger than a Torker II doesn't sound right.
Your distributor is a good quality one. I have it written down in my performance and data log but I don't remember if heavy springs come in early or late. I thought was late.

In Fact, Edelbrock claims the Vortec version RPM Air-Gap pulls from idle to 5500!!!
and reccomended for 262-400cid, so that's why I don't think your 327 should be a problem.

But it does reccomend a 750 cfm carb.
My only other thought is that perhaps the small carb isn't able to supply enough fuel to that manifold at lower RPM - until the secondaries kick in. And by that time your at 3,000 and then it hits like mad pulling to redline.

I'd try swapping carbs first, because that air-gap has a deep plenum and needs more fuel.

jg95z28

The carb is too small. It just so happens I was looking at Edelbrock's website last night for intakes for my 327 67 Camaro. If you go to "Find Parts By Vehicle" it recommend a 750 or 800 cfm carb for that manifold.

For the Performer, it recommeds 600 or 750 cfm.

Get a bigger carburator or switch back to the regular Performer which can handle idle to 5500 rpm with the 600 cfm. If this is basically as stock 327 used primarily for street driving, the Performer will be a better setup in the long run.

racr4jc

I agree, I don't believe the intake is your problem. I would try going to a larger, more conventional carb that is easier to tune. The hesitation you are referring to sounds more like a carb/fuel starvation issue than a parts or combination issue. Sounds like your timing and fuel curves need some attention.

That 327 won't be a big torque monster though. If performance is your goal, be ready to drop in a 3k rpm stall converter and 4.11 gears or something in that range and rev that thing. That 327 will make a sweet motor if you are willing to give up a bit of streetability.

CHPshown67

I am actually planning on going to put a roller cam with508/529 lift as soon as I have enough saved up. I already have World S/R torquer Heads, so I figured the RPM Air Gap and a 750-850 carb was the way to go. I just got impatient waiting for all the money to come in and decided to just get the intake and put it on. Good to hear I wont be having to pull the intake for a third time this week, but a little frustrating to hear the second time was pointless.

Bliggida

You can make an 8 grand revving 302 with 400 horsepower streetable!

327 can make as much torque as you are willing to spend. To my calculations with your modifications you should be making about 390+ horsepower.

CHPshown67

I am also debating holding out for roller rockers as well as porting the Heads. I know the heads are worth it, but are Roller rockers worth it, and if so, whats the best "bang for you buck." I read in Chevy High Performance that stock "1.5" rockers actually are about 1.48's and are inconsistant, ranging from 1.46's up to 1.51's. Can't remember which issue I read it in though.

Timberwolf

Something is not right... I am not sure I buy the bigger is better carb solution everyone is reccomending.

I think before I went that route I would do a little more work on the carb. Is it mechanical of vacuum secondaries? Have you tried playing with the accelerator pump cam? you might not be getting enough fuel in there for off-idle response.
Does your car have power valve blow out protection?
A suggestion, before blowing a bunch of cash on a carb, but a book on carb tuning. It's much cheaper and it should help you a BUNCH.

CHPshown67

I have vacuum secondaries, havent messed with the accelerator pump yet, good idea though, and I am not sure what vavle blow out protection is. The only thing that makes me wonder if anything is wrong with the carb is that i only did an intake swap, nothing else was changed. Would the carb have to be re tuned to the new intake? I know the air fuel mixture would need a little tuning, but i did that.

jg95z28

Well since you're hopping up the motor I'm not going to say what I was going to say, which was "Dude, dump the 625cfm Carter and bolt on a 750cfm Q-Jet"....

Holley w/ Dual-Feed.

It's not getting enough fuel.