Carb spacers

[BIGTWIN]

Can anybody enlighten me on the advantages (if any) of putting a spacer under my carbs to raise them up away from the manifold a little? I have a stock 61 autometic trans. engine with a 4 speed trans. with a Pertronix ignition and dual exhaust. I think that gives me about 90 hp.

[bbodie52]

The purpose of the thick plastic spacer and gasket pair between the hot air-cooled aluminum heads and the aluminum carburetors is to block some of the heat transfer that would otherwise take place. That heat could cause gasoline to boil and vaporize in the carburetors, which would disrupt engine operation.

[classicchevyowner7]

As brad said, it keeps the fuel from boiling. They should be kept on at all times.

[BIGTWIN]

Thanks guys. I guess I should have been more specific though. I have seen references to bigger spacers, some up to 2", and am wondering if these higher ones really would improve performance in one way or another.

[bbodie52]

Here is a link to a lengthy but somewhat inconclusive discussion on the subject, with Dave Motohead at the center of the discussion a few years ago...


http://corvaircenter.com/phorum/read.ph ... 586,541595

[davemotohead]

I have been wanting to spend a day at the dyno and try the different spacers to see if they do anything at all power wise but have not had a chance, I originally had made 1/2" to space the cross over up for center mount carbs as guys were having problems with fan belt changes, I got a request for 2" from a guy so made those,he told me the car ran better with more power but I have not tested them.

[junkman]

......................... I got a request for 2" from a guy so made those,he told me the car ran better with more power but I have not tested them.

Sounds more like the placebo effect.....

[BIGTWIN]

What would a pair of the 2" cost Dave? I'm interested because it seems like the fuel mix could have a little more time to vaporize and cool to me, so I'll give it a try if it's not too $$$$.

[Scott V]

I'm interested because it seems like the fuel mix could have a little more time to vaporize and cool to me,

if the 2" spacer gives the fuel mix a little more time to vaporize & cool - why not run a 4" or a 6" spacer? wouldnt that give the fuel even more time to vaporize & cool?

once after the carb - you need heat or turblanace to vaporize the fuel more. if you cool the fuel it comes out of vaporization. i dont think the spacers are going to do both - better vaporize & cool the fuel.

-Scott V.

[davemotohead]

If anything they would act as a High rise manifold on a V-8 and give a little ram effect, But until they are on the same engine on a dyno with and without them there is no way to tell if they will do anything or nothing at all, I am building a road race engine and once done will get with Ray Sedman and would like to dyno the race engine and a stock engine with/without and see if they do anything at all other than look nice and make for easy center mount fan belt changes.