What makes the Air Gap RPM so much better than the RPM ?

air under the plenum so the oil dont boil the fuel charge..kinda like a mopar intake..

ir path is raised up alittle on the bottom runners and the top runners a touch straighter.

Besides the fuel thing it also makes for a clean install. The wiring for the elec choke, temp and alt can be run under the carb.

Just a FYI, I've had a Edelbrock and Pro Comp airgap intake side by side for a few days on my bench while I was building two motors. Besides the name stamp you couldn't tell the difference between the two. Runners looked the same and the ports were the same size.

Last, I run in brackish water and used a Edelbrock air gap for 8 years. I just replaced it this year due to being taken off and reinstalled to many times but the front water runner (the only place water runs through it) looked fine but I do flush after ever use.

No one has on the dyno or on the water performance and/or driveability differences to report ?

My 1" aluminum carb spacer sweats after a run..The air gap isn't hot like regular manifolds

SB, here you go,
http://www.hotrod.com/how-to/engine/...pm-vs-air-gap/

As has been stated you may see a difference in a hot environment like under a car hood in the summer as the intake charge is separated from the hot lifter valley. Don't know if it's really needed in a boat.

FWIW, I run the air gap on my small block.

I posted the link because they basically found no difference. While we are on the subject, I took a temperature gun and shot my engine after a moderate run, just up against the 4 barrell in degrees:

Ambient temp: high 70s
below thermostat : 140
Oil pan: 190
exhaust manifold: 140
Carb: 55

Double post

That just means the outside of the spacer is hotter and more humid than the inside of the spacer. The air just came the venturis (carb) and is cooler. Big factor is that the fuel just came out of the boosters in the carb and is cooling down the intake charge big time.

Same principle is how Air Conditioning works.

What you are seeing is carb intakes (non heated) run much cooler than fuel injection (mpi) intake manifolds.
Fuel is why.

You'll see the same thing on a non Air Gap RPM with the heat crossover's blocked (if they have them) and running a lifter valley tray.