Posted By: dusterjp
RPM Air Gap Intake Porting - 03/08/14 04:25 AM
Last week I posted an intake question (see below) to find the best one for my combo. The concensus was the RPM Air Gap. My next questions is does anyone know if the Air Gap responds well to porting. If any has any experience (on the dyno or the track) with porting these intakes please share.
Thanks.
Not sure which intake is best for me. I have gone back and forth and can't decide If I should use an RPM Air Gap (ported) or a Super Victor. Here is my combo. 70 Plymouth Duster 418 CI small block. Mild ported Edelbrock heads. 10.9 to 1 compression. Solid flat tappet Comp Cam - @ .050 intake 254 exhaust 262 - lobe separation 108 installed @ 106.5 - lift intake .540 exhaust .555. Pro Systems Carb 837 cfm. 4 sod. - 3.91 gear. This car is always street driven.
Posted By: ademon
Re: RPM Air Gap Intake Porting - 03/08/14 04:48 AM
I don't know about air gap since I never used one, but any aftermarket intake I have used seemed to have a bunch of core shift, and the ports were smaller than my gasket matched heads. So I always gasket match them as far in as I could reach to match the gasket/head. I just did a mopar sb 6 pack intake and the ports look so much nicer now! On a duel plane you won't be able to reach all areas like you would on a single plane.
Posted By: MR_P_BODY
Re: RPM Air Gap Intake Porting - 03/08/14 04:55 AM
Using your gasket see how much the ports are off or
how much smaller... the most I would do is port match
them to about 1 1/2" up each runner from the head
surface... blend them in at that area to the stock
runner
Posted By: qwkmopardan
Re: RPM Air Gap Intake Porting - 03/08/14 09:51 AM
I have had several sbm Edelbrock air gaps and all have been fairly close to the size of the gasket, inner wall, floor and roof, so have never seen the need to even gasket match one. The outer wall is not very close but manifold port is as wide or wider than the pushrod pinch in the head. I often wonder if it would do some good to divide the plenum down 3/4" +/- between the upper and lower plenum on the air gap. Never tried it, maybe someone that has will see this and let us know. For a street car with a manual trans. the air gap would be the best choice and I think you can take it out of the box and use it as is, except like most edelbrock sbm manifolds it will probably need .045 to .060 removed from each side to fit properly. They usually fit great without a gasket and when you try installing them with gasket the bolt holes in the manifold will be way above the holes in the heads. If the holes in the manifold and heads don't line up, neither will the roof and floor of the ports. That is on block and heads that have not had a bunch of milling, if heads and block have been cut a bunch, more than .06 may have to be removed. Worst case I have seen is .110".
The victor 340 must be intentionally choked down at the exit so it can be matched to your liking, never seen one even remotely close to the 1213 fel-pro gasket. Also I have used 340 super victors as well and they are the same as the victor, and need a good gasket match and some plenum work. Seems like the victor 340 is a touch better than the super victor, performance wise. And a Victor Jr 340, I have never seen one, it must be special order.
Posted By: Streetwize
Re: RPM Air Gap Intake Porting - 03/08/14 08:46 PM
There never was a Victor Jr for an LA motor, Fords and Chevies maybe, but not mopars.
Posted By: DragDart360
Re: RPM Air Gap Intake Porting - 03/08/14 11:10 PM
Go with the air-gap for a street car. Better low end torque
Posted By: Rob C
Re: RPM Air Gap Intake Porting - 03/09/14 01:15 AM
I wouldn't cut down the divider on the RPM. The idea is to rcreate more plenum for more RPM. It did work well on the LD340 I have. But the RPM is just simply a better manifold. IF anything, add a spacer.
