Just built 451 stroker for my 68 Cuda (4spd, 3.55's), 440 source kit, Eddy large chamber heads, Engle hyd flat tappet cam (special grind K56/K58 on 114 centerline), Approx 10:1 compresson. I've got a TM6 w/ Holley 850 on it now, but would the RPM air gap yield more torque & better performance? I'm also thinking of mililng the heads for more compression or switching to the smaller chamber eddys. Want the Cuda to be a hot street car that won't see the strip too much.

I cetainly think so.

It's my understanding that Eddy has designed the Air Gap to make torque like the dual plan that it is and support high rpm like a single plan.

With your gearing I'd pick the Air Gap. The TM-6 would respond better and be stronger in the quarter with 4.10s.
It's a good intake don't throw it away!
R.

RPM AIR GAP ????

Don't all big block mopar wedge engines have an "AIR GAP" intake by DEFAULT ????

just thinking out loud

OOPS! RIGHT, NO AIR GAP for 400s. You'll have to block the exhaust crossover to get max benefits but still a great manifold. Air gaps and regular Perf RPMs have AFAIK the same interior configuration as far as ports and plenum.
R.

Imight install 4.10's & Gear Vendor's overdrive next year. Then I could use the TM6. One friend said w/ the TM6 would feed the larger cubes & longer stroke than the 383 RPM air gap. Would the dual plane intke need to be ported?

Try it and see, I bet you'll like the Performer RPM so much that you won't go back to the single plane. On a street driven car you can really feel the difference the RPM intake will make down around 2000-3000 rpm. At the drag strip the single plane may or may not be faster, a lot depends on the chassis and the gears. But on the street you'll really notice the extra torque down low.

Thanks Andy. I'll order one from Jegs today. Would you recommend I have it ported for the extra cubes & stroke?

My son loves the Performer RPM on his 400 Dart. It ran a tad quicker then the Street Dominator did by about a 1/2 a tenth even though it had less mph then the SD. The 1/8 and 60 ft were much better with the RPM and it was enough to keep the 1/4 et quicker then any single plane he tried and the SD was the best single plane on his Dart. He will never go back to a single plane on his combo he says even though I have out 60 ft him with the SD on my 63. But honestly Andy is so right as the RPM is great for a mild street/strip car. Ron

Plus, Andy was in another life known as "451boy"!!! But do a websearch on his real name and look up his dissertation. Not a forged piston in sight in that gem!


R.

You don't need to block off the exhaust gas crossover since you're using Edelbrock heads. The E heads don't have the crossover in them so you're good to go. The Performer RPM intake should drop on there without any issues using a factory bathtub style intake gasket.

There is also the Mopar Peformance version of that intake. The MP intake is exactly the same except it has some cool lettering on the front that says MOPAR WEDGE. It costs a few bucks extra but the lettering was worth it for me. The MP unit doesn't seem to be very popular for some reason. I'll post a picture of the one I have since I think it looks cool.

Andy, thanks for the input. Does MP still make the intake you mentioned? I've never heard of it or seen one before. Its the same inside & out as the Eddy RPM airgap? The TM6 looks pretty cool, but can't put a bigger cam due to smog regs in Reno. Thanks for posting a picture if you have one.

Sorry, I made a mistake on the intake. MP only sells the RB version of the intake and you have a low deck motor. I'm not sure why MP doesn't sell a low deck version but I guess they decided not to have Edelbrock cast one for them.

I've asked why no low deck mp intake, didn't get an answer

The MOPAR WEDGE lettering is cool. I hadn't ever seen one before and then I stumbled on one at a swap meet. The picture in the catalog doesn't quite do it justice. I don't understand the lack of the B version either, maybe they just ran out of tooling money for the year or something.

Here is a picture of the RB version.

Yep, that is part number P5153525.

There is a shot of it on page 62 of the 2007 MP catalog, but I like your picture better!

Oddly, it can actually be bought for less than Summit charges for a regular RPM intake, but you need a good guy parts fella who will sell at a small percentage over dealer net. At retail it's higher priced than Edelbrock...but after a little digging, I found it to be sometimes lower priced, depending on who was selling it.

Personally I would really like a B version for my C body, but there is no such thing

Yep, intake prices vary quite a bit sometimes. I just bought a Super Victor from Mancini for $290. Summit's price was $360 for the same intake. So it does pay to at least look around a little bit.

That 525 intake in the picture above was purchased at a swap meet for $100. It appears to have been used once and then evidently the guy didn't want it anymore. Nice score for me!