Do these really increase the bottom-end & mid-range when used on a dual plane intake like the Performer RPM? Have a 2" lying around and I was wondering if it would help my 3.08 geared car.

I put a 1" 4 hole spacer on my RPM intake, and it helped idle quality and bottom end response, then switched to an open, and lost some throttle response and judging by my Levi's it helped upstairs. If you have it, it won't hurt to try it and see for yourself. graemlins/thumbsup.gif

Thanks ZZ69chevelle. Will give it a try.

I used a 1" 4-hole phenolic spacer with my Holley 300-36 dual plane. 60's dropped from 1.90 to 1.70 when I took it off.

Chris