To spacer or not to spacer, that is the question

[unclewill]

My new Edelbrock Performer RPM is completely divided in two up to the carb mounting flange.  I have an open phenolic spacer about 1/2" thick I could mount under my 850 Holley, or none at all, or I also have an extra thick 1" 4-hole aluminum spacer which may fit under the hood (not sure).  Hmmm...what to do...no spacer is my preference...any thoughts?
482 stroker, BBM heads, Comp 292H cam, 10.3:1, looking for big midrange torque in a 69 Torino Cobra street machine.

[Drew Pojedinec]

Living in the south, no spacer isn't an option due to heat percolation on shutdown in the summer for me.
I will also mention that I've never seen an engine run worse because of a reasonably sized spacer.
I've got about 20 spacers on the wall I like to try out just for fun when I get a new engine.

I'd think a 4 hole spacer .5-1 inch would work well, tapered would be even better (phenolic material is my preference in Satan's Armpit, Georgia).

In the end, whatever you want to do I'm sure will be fine

[428 GALAXIE]

Hmm that heat issue was a bit problem to me too what do you do when dont have enough clearance between hood and air cleaner.
Had a 1" phenolic  spacer before but with rpm intake it wont fit under hood.

Sorry for robbing the post.

Mikko

[Drew Pojedinec]

https://www.summitracing.com/parts/edl-9265/overview/
Edelbrock heat insulating gaskets are 1/4 inch thick and work pretty well.
Want to try one out?  I've got a few used ones that are still usable, just pm me your address and I'll send ya one.

I also used a 1.75inch drop base filter with my old engine, it worked well and I could use 3/4inches worth of spacer with no issues.



No airflow issues with this lid.


Dunno what I was doing there... surprised the OCD in me allowed the wires to look like that for a photo.
Insulating fuel lines helps.  Electric fuel pumps help (simply because the fuel isn't in contact with the hot engine block).

[cjshaker]

Want to try one out?  I've got a few used ones that are still usable, just pm me your address and I'll send ya one.

Sorry for sidetracking, but you don't see this sort of thing on any other forum than the FE forums, from what I've seen. I've done the same and had others do it for me. Great guys.

[428 GALAXIE]

Thanks Drew but i`m so far away that gasket will cost more than 10 new from our local speed shop,which is 220 miles away.But i appreciative you`r offer

Mikko

[unclewill]

The car has factory ram air air cleaner assembly which I'd like to keep...I'll try that 1/4 inch gasket though.  A local pal suggested cutting a notch in the intake.  Funny, with no connection between the two halves on the intake or exhaust side it's almost like two four bangers sharing a crank...

[unclewill]

Any thoughts on notching the divider in the intake?  Jay?  Anybody?

[Drew Pojedinec]

The spacer I'm sending you is cloverleaf, so there is communication between planes.

[unclewill]

Thanks Drew!

[My427stang]

I run mine notched with a matched spacer, no loss of low end with the 489 it was originally on, and the 445 it's on now will pull right down to nothing, but pulls hard on top.  This RPM has also had work in the ports and roofline of the plenum





How you see it on the bench is how it is on my 4x4 F100 445, 1000 Holley, 1 inch shaped spacer, no issues with power right off idle

[unclewill]

So is that the point of the notch, enhanced bottom end/off idle torque?

[Joe-JDC]

With those cubic inches, the torque is not going to be an issue with the slotted spacer, but on a typically smaller engine, it will lose low end torque, but be up in horsepower over a four hole.  On dyno tests of every imaginable combination of spacers up to a total of four inches, we found that each engine responds totally differently depending on compression, camshaft lobe centers, and cubic inches.  Even same engine families respond different depending on airflow requirements with a dual plane intake.  Joe-JDC

[unclewill]

Hmmm...because slotting the intake is irreversible, I think experimenting with spacers is the most prudent course here.