The spacer I used on my performer is just an inch alloy one with the divider in the middle, runs beautifully, pulls well especially down low (then again I'm not really interested in driving hard these days) Personally I can't see any real use in doing that mod if you're going to use an open spacer anyway, as that space under your carb would be working similar as removing that area from the divider in the intake. Also I remember many years ago, people doing a mod of removing most of the divider on a performer intake that was supposed to be good for a cheap power gain. I knew of one guy who did this and he reckoned it was a load of BS and the car actually lost power. If you look at a Shelby/Blue Thunder dual plain for a Cleveland, the only place they are machined is on the divider, in between the secondaries and these intakes are a standard type (no air gap) dual plane, and these intakes are known for making power until around 6800 RPM mark.
