Air gap or performer rpm??

They are the same intake. If your not running the heat cross over, and your not with the Indy X heads, the AG will gain nothing. The big empty cross over is as effective as the AG. I have built 2 stroker small blocks this summer, one with the RPM(non AG) and one with the Weiand Stealth. They both made 560HP and 550TQ.

But in the end they are the same. Same ports, same core, same port volume. Save your money or put it somewhere else in your engine to get more power.