Potential new Tunnel Port intake

[Stangman]

I agree with Doug and Im going to throw in intake manifolds also. I mean we are all waiting for the BT 2x4 intakes to get here and whats there gonna be 100 made with 300 people waiting, I mean just saying. Come on Jay
a nice Jay Brown 2x4 medium riser intake. PLEASE!!!!.  Just throwing it out there what do you think?

[Joe-JDC]

An RPM Air Gap 8V where you could mount the Holleys in line would be an excellent all around intake for the FE even though the BT looks like the Ford original.  Joe-JDC

[Stangman]

But you can’t right Joe.

[mbrunson427]

But you can’t right Joe.

I fiddled around with this a bit because I was planning on machining out the whole top of the Edelbrock air gap intake and making an adapter plate (exactly the same as what Dove did when they made their removable top tunnel wedge intake). I was going to make a 3x2 top plate and a 2x4 top plate. The problem I ran into is the length of the top plenum is not long enough. If I remember right, it needed about an extra inch from the front to the back of the carb pads. By the time you space the carbs out, the front carb is further forward than front of the runner for port #1. It'd require cutting that runner and welding on more material which I wasn't interested in.

The only way I can see doing it is making an offset spacer that is between 1/2" and 1" tall (depending on how fast you care to transition). I didn't really care to do that either, so the idea was abandoned.

Here's a quick illustration of what I mean....


Long story short....I agree, it'd be nice if someone made this same dual plane intake with holley carb spacing and a removable top that a 3x2 or 2x4 plate would fit to. The tunnel wedge intake is too much for most street motors and they're almost impossible to find.

[andyf]

If you use dual throttle bodies a lot of the spacing issues go away since you don't need the fuel bowls. Also, the throttle bodies tend to be shorter than carbs so there is more room for the air cleaner.

[Stangman]

I wonder if the new Fitechs would work. Is the edelbrock a medium riser port

[fekbmax]

I don't know how much of a market there is, but the timing of your post is good - Vintage Cylinder Heads just announced yesterday in the old FE Forum classifieds that they will have new Tunnel Port aluminum heads available in about 4 months. No word from them if they intend to market an intake manifold too, so demand for existing manifolds may increase. Details are a little slim yet on the new heads, looks like they will come with 2.09" & 1.66" valves, no word on if larger valves will be offered.

Wonder what became of this ??

[C8OZ]

Old thread, I know. 

Ran across this old project on a Pontiac group, and it got the wheels turning again.



Edit: Not sure if they're still making parts, but here was the source - https://www.dcimotorsports.com/products/dci-ram-air-five-parts/dci-ram-air-five-intake-manifold/

[wayne]

 Offenhauser 5880 adapters should let you put holleys on a rpm air gap i am sure you will lose some flow.But factory air cleaner and linkage should work.

[Joe-JDC]

I have ported the RPM 8V Air Gap, and balanced the runners.  That manifold will out flow a ported MR 8V by a good margin.  I wish Edelbrock would cast one with Ford Carb spacing.  Nostalgia aside, Edelbrock has vastly improved their intakes the last few years.  Joe-JDC

[wcbrowning]

How does the RPM 8V Air Gap compare to a Tunnel Wedge, both stock and with similar effort and prep?  Is there a big difference between a Ford TW and the BBM TW?

I have ported the RPM 8V Air Gap, and balanced the runners.  That manifold will out flow a ported MR 8V by a good margin.  I wish Edelbrock would cast one with Ford Carb spacing.  Nostalgia aside, Edelbrock has vastly improved their intakes the last few years.  Joe-JDC

[wayne]

I have a 8v rpm air gap on a 308 ci small block with two 500 cfm edelbrocks and it runs the best it has.The big shock was how much low end its got over the old torker i had a victor jr and a f4b on it also it beats them all.The engine is not much just windser jr heads out of the box and a lunati 292-512 cam.

[Joe-JDC]

How does the RPM 8V Air Gap compare to a Tunnel Wedge, both stock and with similar effort and prep?  Is there a big difference between a Ford TW and the BBM TW?

Finding a stock Ford TW is nearly impossible, but the originals flowed ~380-390 cfm as cast, but ANY gasket matching caused the flow to jump to 410 cfm UP to whatever size you felt you needed.  However velocity dropped big time and torque went away to the tune of as much as 35 lb/ft on a 390 cubic inch engine.  The BBM is bigger as cast, and flow starts over 400 cfm, but I will not quote numbers.  Joe-JDC

[Joey120373]

The 8v rpm air gap with dual TBI set up looks promising, outside of the fuel injection complications. I imagine though, with a bit of clever wiring and the right controller, you could get the best of both worlds. Charge cooling And the ability to trim individual cylinders. This would require a TB that is just the throttle valve and injectors, not one of the fancy all in one self tuning jobs that are all the rage these days. Then wire each injector as you would for a sequential port injected motor. Glad to here Joe say that the rpm air gap is indeed a really good manifold, I wonder how much work it actually needs?
I have never seriously looked at that manifold because it forces you to use ( in my humble opinion ) pretty crappy carbs. Don’t get me wrong, those carbs have their place and for a gut that just needs a carb to get from point a to point b, they are fine.
Did anyone see the engine masters where that compared cheep carbs? The summit autolite clone did pretty well if I remember correctly, would that carb fit?