I used a .750" plate and set .450" of it into the plenum and it raised the carburetor .300". If I ever do this again, I will use a 1" plate and raise the front of the spacer an additional .250"-.300" so that the carburetor sits level on the manifold and is not tilting forward. It'll mean I have to realign the carburetor mounting bolts to set perpendicular to the altered surface, but that is why God made heli-coils.
Of course I'll be testing the 2" HVH Super Sucker spacer also. So far every engine I have used the 2" on has made more power over the entire rpm range.
