1. Ray Johnson · March 15, 2013

    My setup consists of a mildly modified 351W with a Performer RPM dual-plane intake, a 2″ swirl torque spacer, and a 1406 carb. Would I benefit from a 1/2″ open spacer between the swirl torque and the dual-plenum? Thanks.

    • admin · March 15, 2013

      First of all, the #1406 is not recommended for the following intake manifolds: Performer RPM, Performer RPM Air-Gap or TORKER/TORKER ll. Do to its efficient/fuel economy design, customers can encounter a lean condition that may be challenging to resolve.

      Now to answer you question,

      It is always (in most cases) recommended to use only divided or 4-Hole style spacers on dual-plane intakes.

      Using an open spacer on these types of intake manifolds can compromise the effectiveness of such designs, and reduce bottom-end and midrange performance.

      So as a general rule, we would not recommend you use an open spacer unless you are only looking for upper RPM performance, and are willing to sacrifice bottom end/midrange.

      Please note: We (Edelbrock) have no test data on the swirl torque spacer mentioned. And do not offer one in our line of spacers and adapters, so it is challenging to comment on something you have not tested,.

      Please feel free to call our Toll Free Tech Line for further details.

  2. mike · March 15, 2013

    What is the recommended spacer (divided or 4 hole) for a performer rpm manifold for a street car running an automatic tranny. I am using a 1406 carb that has been rebuilt to 1405 specs as a baseline and then tuned from there.
    I am currently running an open spacer because I did not realize that i was negating the dual plenum design. I know realize why it took me so long to tune the carb.

    • admin · March 15, 2013

      We would recommend the #8723 (4-Hole design) .500” thick as long as you are using a single drilled carburetor pad based performer intake. If it is dual drilled (such as our #2101 for SBC), than I would recommend our #8725 (divided design) .500” thick