RPM Airgap?

I just switch from that intake on a 318 with 360 heads to a RPM non air gap with keeping the exhaust intake heat open on both intakes. I feel the motor is more enjoyable to drive that way even if I lose 10hp. I have no heat related problems either.

Well heres my take. The idle smooth out, even cold. Low rpm power is better but it did seem a bit softer on top-6000 rpms. My overall power is better but with your 3000 stall speed, I have 1800 but 3.91 gears too.

I am using a 750dp, I know dual planes like big carbs so that 650 might be a bit small too but for your intake now its prefect.

I would leave it alone...you could try it. My gas mileage went from 9 mpg to 10mpg with the RPM. And it does idle better in gear but again I have a lower stall speed than yours