March 13, 2006 at 10:20 pm
#60447
Paul,
As a general rule, a spacer between the manifold and carburetor increases HP and the the thicker the spacer, the greater the increase. The other purpose of a spacer is to reduce heat transfer from the manifold to the carburetor; a phenolic resin impregnated fabric is the traditional material to reduce heat transfer.
I doubt seriously that you will be able to use a one inch spacer with the F4B. Try putting some SOFT Styrofoam on top of the air cleaner and then GENTLY close the hood. Add or remove Styrofoam as needed until you figure out how much clearance you have for a spacer.