Jim Bureck mentioned a big HP increase with a 4 hole spacer and a little cut from the divider on his s-divider manifold. I can't find it, but it was on this site.
Here is some dyno info on the 4 hole spacer... It seems to work well on both the ta and poston intakes.
Jim Bureck cut 1" down into the divider of his manifold and used a 4 hole 1" spacer with great results. I found this in my notes but not the web location. The S-Divider is a unique design. This manifold just needs some testing to get the full benefit. I suspect there is more potential in it. My info so far goes like this for Edelbrock. These spacer mods need to be tried with the s-divider as well. 1. Open spacer: Not good on most Edelbrocks manifold applications. 2. Two hole spacer: It's a 4 hole cut front to back on the left and right. This a "best modification" by Jim Hand, noted and pictured in His Pontiac Performance book. Jim Weise showed some interest in this if I recall. May help front-rear fuel distribution & may be the best idea yet. 3. Three hole spacer: A 4 hole cut between the back openings to form a single wide oval . I recall someone saying this provided good low end grunt and helped top end as well, but know of no proof. Sounds good though. 4. Four hole spacer: Better than open spacer on an Edelbrock, but no spacer was a tad better. Another person said it helps off-idle and low end drivability. Do not use plywood spacers as mine collapsed 1/16" on one corner and that can warp a carb or cause a vacuum leak. I threw it away. Aluminum spacers do not insulate well. Try a JOMAR # 5051, 1/2" phenaulic for $30.00 and modify it as needed. LOVE TO SEE SOME RESEARCH GOING ON THIS. Good info for a future book.
