On the 396. Thought you might be interested in the results.

https://www.thirdgen.org/techbb2/sho...hreadid=320131

The Action+ was gasket matched. The RPM is slightly smaller, about an eighth of an inch wall left all the way around each port. Didn't seem to hold it back much, though.

 

I've been saying for a while now that the air gap is the best intake for street small blocks. Seen lots of power gains with them over even the Perf. RPM. Glad to hear you had good luck with it.

 

I was also considering the Stealth. It would have been cheaper, but I liked the idea of the Air Gap for bracket racing. I was hearing less than complimentary things about Edelbrock quality control a couple of years ago, but hadn't lately, so that helped with the decision. I did have to file down the upper bolt bosses in order to clear the cover rails and covers themselves (cast aluminum), but that was minor. Also had to modify the upper alternator bracket (elongate a bolt hole), also minor. The carb mount was slightly higher, so I had to go to thin carb gaskets on each side of the Holley carb shield.

The really good news is the coolant bypass hose fit better...

 

I just did a similar swap on my 355.Well it was the Stealth to the RPM air gap.The main swap was cake, no major issues there.I cannot beleive the difference in the car after the swap.I had the car well tuned with the Stealth..but driveability was always "lacking".I could never really get the car to come off idle well.And when I finally got it "ok" it was pig rich on the initial launch.Lean it out and it got worse.The looks are a bit better to me as far as when the hood is open.Driveability though has improved what feels like 100% on my mild street motor.I set the carb back to factory settings aside from a blue primary pump cam and going down to a 28 primary squirter when I put the air gap on.This car drives like it never has.It runs so much better down low...excellent in traffic manners when I am stuck in town.It used to get grumpy with the Stealth.It doesn't seem to pull as hard in the mid range but it seems to get up in MPH quicker.Flatter torque curve maybe.Results cannot be verified till I get back to the track so we'll see.But from what it gained from the swap in improved street manners alone was more than worth it.Excellent choice!

 

yeah the Stealth is too much for a small displacement street motor. Throttle response and driveability will suffer. I've noticed in the past week or so that once the Air Gap is warmed up after the motors been running for a few minutes, the power gains between it and the RPM are almost non-existent. I figured keeping the plenum up and away from the hot lifter valley would keep it cool, but it's not enough to see much power.

 

I myself never expected or have been convinced that the air gap will make more power than the standard model once fully warmed up and under a hot hood.Maybe in a cool dyno cell...but not in the real world.I wanted the air gap just for the looks myself.Call me vain.If not for that..I would have the original RPM underhood right now.

 

In my case, the real world doesn't count - I drag race this car.

 

It's real world enough.It's bolted in the car under a hot hood when racing!!lol

 

anyone tried some how cooling the gap? Like some put ice packs or something on intakes, some tubo guys put them on the intake pipes and what not. You could probly see some real gains then. What concerns me about them is all the junk that collects in the motor will go under there and hide and make a nasty mess over time with out care to attention when cleaning under the hood.

 

The intake needs a little heat in it to work properly. Otherwise, fuel will puddle, or won't vaporize properly on its way to the intake valve.