I also wondered about the difference. This is from a previous post I had and my own dyno comparison.
"So where was the best power made-Dart or Airgap? I've got a Team G and also an airgap for my 468 and can't decide which I should run..."
I'm not sure of your combination and after having my dyno run (firm believer) it helped in ending speculation. This is what I had posted previously and got the idea for comparison.
"I agree with hotrodf1, I have an old article from Hot Rod november 1990 called "The Lash Word" (yes it's a bbc write up). The 454 engine used was a "Sat. night special" and compared cams (hyd,solid,roller) and also oval port intakes (weiand 8013,torker II,Holley strip dom, Dart). Now the hyd cam was healthy (comp cams 292H) that even at low rpm Dart hp& torq equaled if not bettered the the dual planes.
So when I saw that I decided (with my sat. nite special bbc 427)on my dyno run I was going to compare my edelbrock rpm with a Dart intake (oval port). The Dyno guy figured the rpm would be the only way to go. But after the dyno pulls we were both surprised and he said the Dart was the way to go. With the rpm intake the right and left A/F ratio was off.. Yes staggering the jetting might of worked but the dart was right on. Now every application is different, but after the dyno run it made me a little more open minded."
Now the tq started earlier on the air gap but the peak hp occured about the same rpm as the dart. Air gap 525hp@6400 500#tq@4300rpm. Dart 540hp@6300rpm and 500#tq@4600rpm and again the a/f ratio was off on the air gap. I'm not saying one is better than the other but in my application the dart worked and your results might be different.