Carb spacer
More Turbo
Joined: Apr 2011
Posts: 707
Likes: 2
From: Sauk City, WI
As Im fairly certain you have a Performer, so you have 2 holes, kind of oval shaped on one edge. And man, thats a big chunk of aluminum, heh. I would go with the 4 hole design, but being that your intake has a slightly different setup than say an intake from a SBF, you may be able to use the square hole design.. As far as I know, there is no 2 hole 4 barrel carb spacers. The single square holes are designed primarily to be used on single plane intakes like a Victor or a Team G.
But I would still give Edelbrock a call. It cant hurt.
But I would still give Edelbrock a call. It cant hurt.
Posting Guru
Joined: Jan 2011
Posts: 1,670
Likes: 8
4 hole starts building torque lower in the rpm range and through out the rpm range, where the open spacer does it's work higher in the rpm range. Open spacers work the same as the ram log idea but on a much smaller scale. Unless you plan on racing the motor or the motor was built for that purpose, AND you do not care about fuel mileage or real world streetblility, by all means, mount that 'open' spacer. There is another thing that is sometimes overlooked when mounting carbs and that is the gasket. If you are running a dual-plane and a 4 hole carb, use a 4 hole gasket or your unique 4 hole design is down the toilet. This will cause an inner vacuum leak that will cause poor idle, poor performance, poor A/F mixture under the carb. Same with using the 'open' vs the '4 hole' spacer. Keep it divided if you plan on real world drivability... Or not.
A '4 hole' pulls harder on the carb = leaner jetting = good streetable performance
A 'open hole' = fatter jetting needed = not as streetable untill high rpm band.
There is a lot of science out there on this subject - just need to look.
A '4 hole' pulls harder on the carb = leaner jetting = good streetable performance
A 'open hole' = fatter jetting needed = not as streetable untill high rpm band.
There is a lot of science out there on this subject - just need to look.
More Turbo
Joined: Apr 2011
Posts: 707
Likes: 2
From: Sauk City, WI
Great explanation Masked Rider. Thats primarily why most run a dual plane intake on a street motor as well, because they have much better low end torque. The single planes are much better at higher RPMs and making horsepower.
There are some really unique carb spacers that have come about in the last few years that will influence the way the motor runs at different RPMs.
There are some really unique carb spacers that have come about in the last few years that will influence the way the motor runs at different RPMs.
Cargo Master
Joined: Apr 2003
Posts: 2,389
Likes: 58
I don't agree with the internal vacuum leak statement. My manifold has a small square window cut between the two sides. It idles great, performs great, has great mixture. Quite a few manifolds are set up similarly. I've run an open gasket with a 4 hole spacer with no noticeable differences.
But I agree that you want the 4-hole. You can even take it further by tapering the spacer to match the intake as best you can. Or if the manifold is actually smaller than the spacer, get a smaller spacer, or pull the manifold and match it.
But I agree that you want the 4-hole. You can even take it further by tapering the spacer to match the intake as best you can. Or if the manifold is actually smaller than the spacer, get a smaller spacer, or pull the manifold and match it.
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