Is an air gap manifold needed?
 

My carbed 502 should be about ~550ish hp and currently has a Performer RPM non-air gapped intake. I see that Edelbrock offers an air gapped version and I have plenty of room under the hatch. Is this something worth switching out when I swap cams?

Also, I read that the RPM manifolds tend to not respond real well to a carb spacer and was wondering if anyone here has any experience with that.

Tia.

550 HP with a dual plane intake? How many RPM? I'd be looking at a single plane intake.

The 550 is an optimistic number on the crate motor of 500, and maybe the EFI525 cam will get me higher. Realistically, my guess now currently is about 450 at the flywheel at best. Should I be looking at a single plane instead? Performer RPM heads Oval port 9.6:1 static.

The Vic jr has been out powering (on the water) both the RPM intakes on approx 450hp 454's and higher.

Same reason open spacers on the dual planes on same motors will make more power (on the water) but people with Widebands have reported this really screws up their already screwed up bank to bank A/F ratio.

http://www.edelbrock.com/automotive/...mages/2902.jpg

They even have that in Oval port, but more importantly looks way cooler than that truck motor manifold, lol. It is a full roller engine so would this be spinning higher rpms?

^^^^

going to the air gap version won't gain you a thing..someone did that test a while back, the single plane may be a different story

I'm trying my Air gap next season. That's a 600hp 454. Used to run a single plane Team G, If I don't like it it's easy to go back. But I bet throttle would be a little easier in the docs vs. a single plane.

I guess more specifically I'm wondering if the temperature difference is enough to justify trading out intakes. I haven't had any vapor lock issues so I guess I don't have a specific problem I'm trying to solve.

With a bit of googling it seems that milling down the center divider on the dual plane giving it a touch more top end.

Dynoed a 468 2 weeks ago, old single plane and air gap made the same HP at the same 6300 RPM. The dual plane made 45lbs more torque at 3000 rpm, was ove 500 from 3000 to 4300, single plane broke 500 from 4100 to 4300.