Been away from the build for quite a while, but I'm trying to get going again. My question is, how much clearance from the rocker arm bolts to the underside of the valve cover is needed? I'm going to be using stamped steel covers that I welded up to resemble the original cars, but with the new valve technology, I know that I'm going to need a spacer. Question is how thick will it need to be?
Sorry for the dumb question, but I've been battling with this for some time, and I want to tie up the loose ends on the engine so it's ready to install hopefully soon.

Rick