I was looking at Jegs online catalog and saw the AirGap intake manifold. I was curious if anyone knew if this actually worked in cooling the air or if it is just a gimmick.

 

It's not a gimmick but the benefits on a street motor
are questionable. A little heat is needed to help fuel vapourize
in the manifold while idleing and cruising. This heat really helps the mileage, smooth cruising and emissions.
The carb flange height is a little higher on the airgap manifold
compared to the normal rpm intake.
The air gap intake just takes longer to heat up.
For drag racing where ya can cool the runners with dry ice
between rounds, there is a benefit (cooler denser air charge) but for street driving I don't think it's worth it.
I had one for a short time (traded for a non gap vortec version when I upgraded to vortecs.)
It does look beastly though....!

 

Supposedly the benefit is not only the cooler charge but also an improved runner design over the base RPM.

I still havn;t seen any good reviews of it yet, niether for good or bad

 

I have one on my car and I like it I guess. I made the switch when I put on the vortec heads. What a difference! Do you have vortecs? I had the regular RPM before. I think that the intakes are about the same as for performance. Either way they are great intakes for street motors.