Years ago I read in a car magazine that GM put a tin heat shield underneath their quadrajet intake manifolds to keep hot oil from splashing on the underside of the intake runners and disrupting fuel distribution, so I put one on an Edelbrock aluminum intake and engine ran noticeably smoother.

Of course I sold the car that had that intake on it because sometimes I do stupid stuff.

Anyway my fuel was disappearing from my Edelbrock 600 cfm carborator fuel bowls after a few days of sitting and I suspected it was either leaking down through worn jet needles or evaporating due to boiling away.
So I added one of those resin spacers to see if that would be of any help and the problem seems to have disappeared.
I'm only mentioning all this because I needed to let somebody know that my retired fat bottom doesn't just hop up under the hood anymore and next time I'll just live with the problem.