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My 55 stock 239 V8 has a 1/2 " spacer under the carb ( about 8 gaskets stapled together). I know this is not factory and the spacer supposedly helps the fuel to mix better with air.
Anyone else running a carb spacer.
I am running a 1" phenolic spacer in my Caddy engine. To make the engine fit under the stock hoods the Caddy engineers lowererd the center of the intake manifold, so much so that gas actually has to go up from the carb to get into the heads. One best things you can do for my engine is to go with the high rise Edelbrock intake manifold. I of course do not have that kind of cash (still saving up for it) so I opted for the 1" riser.
Basically its a very small tunnel ram. It can't hurt, and can also help to isolate heat from the carb.
They can help and never hurt unless the bore size is smaller than the carb bores (larger is OK). A solid spacer is less likely to develop a vaccuum leak than stacked gaskets tho. Summet sells spacers to fit most popular carbs.
I've got a 1" and 2" spacer. I've used both and don't find a difference as far as performance. I noticed a little smoother idle with the plate versus no plate at all. I know the early Ford small blocks use the plate for a vaccuum source for power brakes. It was also used for clearance of the throttle linkage arm at full throttle to clear the manifold. I've kept the 1" on my engine and like the looks of the carb being a little higher on the manifold.
Not sure what type of spacer your using, but you have to make sure the surface for the carb and manifold are perfectly flat and true. Otherwise, you'll get vacuum leaks. Any of the auto parts sell them (Mr. Gasket) for about $20.
Runs great. The aluminum spacer made a big difference. I thing the old spacer, made up of about 8 gaskets stapled together, was leaking.
End of Thread.
As stated earlier, spacers can be good or bad. Make sure that your spacer matches your manifold. If the manifold has separate bores for each throttle plate, the spacer should also. If you use an open chamber spacer between a manifold with individual bores and your carb., you can end up with rough idle and/or off idle hesitation. This is particulary true of the dual plane designs. If the manifold is an open chamber design, then either design should work fine.