Carb spacer... Aluminum or Phenolic?

[1trickpony]

Aluminum or Phenolic
Open or 4 holes?

[Barry Donovan]

aluminum

[BlackoutSteve]

My choice would be phenolic for less heat transfer/better insulation.
4 hole for stronger vacuum signal, less plenum volume and more for lower rpm.
Open for more plenum volume and higher rpm.

[Stich496]

Aluminum or Phenolic
Open or 4 holes?

depends on engine set up..
it's trial and error..
wilson 4 hole is very nice, makes power and is pricey

[1trickpony]

I am just looking for less heat transfer, and probably low end if I had to choose.
So pheonic 4 hole?

[Beagle]

MDF... and experiment ?

[DanStokes]

You will have to experiment and see what works with your setup. I made a phenolic spacer using regular wood working tools - no big deal. As Beags said, you can make 'em out of MDF for cheap and see what works - it has similar properties to phenolic but is much cheaper and easier to work. Try an open and closed one and see how your engine responds then you can make/buy a phenolic one (I think the MDF would eventually deteriorate). Fun project and an excellent tech thread for BangShift - maybe get data on a strip if cheap dyno time is not available.

Aluminum will transfer heat like crazy - that's what it's good at. If the goal is to keep the carb cool, not the way to go.

Dan

[mustang13]

Jeff, NAPA use to sell a Holley flange carb gasket/spacer, was like a 1/2" think, made of paper-cardboard-wood like material and worked awesome on low rise dual plane intakes.

https://www.napaonline.com/Catalog/CatalogItemDetail.aspx?R=BK_3353723_0006391677

Moroso is stuff is top notch too, IMO.



A short open spacer over a dual plane will speed up intake velocity and plenum balance.

Beware of JEG's/Summit brand "Phenolic" spacers, most are just plastic that is unstable at high temps and will warp. I found this out the hard way when a Jeg's spacer warped on me cracking the baseplate of the carb.

That said, the best carb spacer to use has spray bars and solenoids hooked to it, and makes more power than any other spacer! : )

[ROY]

A lot has to do with you manifold,single plane or dual plane,and what RPMs you want the engine to work best.I have done extensive testing on my drag race engine using a Victor jr.manifold and 750HP.The car is a 4-speed,leave at 6600,shift at 7200,out the back at 8000.My conclussion was a 1" spacer in either 4 hole or open made no difference on the track on the same day.I ended up with a tapered 4 hole as that was on the engine after the final tests. ROY.