dcohen

when I got my mustang it had a factory 4bbl intake and carb on it. the carb had a bout a 1 inch spacer under it. I am putting a edelbrock performer RPM intake on it and I was wondering If I should put the spacer back on.

nba1341

Uhhhh if its still going to fit under your hood then I'd say go for it.

Stops fuel boiling over and can increase your throttle response

Jonk67

If you can't fit the 1" they also make a 1/2" phenolic spacer, something is better than nothing. Adding the 1/2" to my carb. dropped the temp of the carb dramatically. Before I could hardly put my hand on the carb., it was as hot as the intake, after I could lean on it, warm but not burning hot. Cooler fuel is better.
Jon

kalli

all of the above :-) use it if it fits, if not use a thinner one

Starfury

Do NOT use the factory aluminum spacer on an aftermarket intake. Edelbrock has a tech bulletin concerning vacuum leaks resulting from doing this.

Get yourself a good phenolic or composite wood/resin spacer. The RPM is a taller intake, so consider a 1/2" spacer instead of a 1". The primary goal is to keep the fuel in the bowls from boiling.

dcohen

I have a 3 inch cowl hood, so I dont think clearance will be a problem. The spacer that I have is the factory aluminum spacer. Will an aftermarket spacer have a place to hook up the pcv valve?

kalli

good call starfury. i thought i read hsi was phenolic, not alum

I bought the edelbrock phenolic and it didn't have the thread for a NPT pickup. I've seen one on a car show 2nd hand that had it, you could always hook the PCV to manifold port on carburetor in case you don't use it

dcohen

my bad, it is an aluminum spacer and not a phenolic spacer

dcohen

which spacer would be best? an open spacer, a 4 hole spacer, or a 2 hole spacer?

Jonk67

Sounds like you're fairly stock I'd go with the 4 hole or 2 hole for a dual plane manifold, open spacer is for top end and a single plane manifold basically. You probably wouldn't be able to tell the difference in driving between the 2/4 hole if the 4 hole lines up with the venturies at the base of your carb.

You never did state which carb. you have make/model, many have a port for PCV on the carb base. The phenolic spacers don't have the hookup, not the ones I've seen from Summit, etc.
Jon