Since you're into fabricating stuff, here's another idea for how to go. My buddy made this heat shield out of sheet metal. After he figured out his problem was engine timing, he gave it to me. As you can see, I also had insulated my fuel line with slit rubber fuel line wrapped with real duct tape. It all helped, but, for me, the ultimate fix was to get one of the more-modern Zenith carbs, made for many applications but most frequently bad-mouthed on this forum as the "forklift carburetor."
FWIW, here's a picture showing that the vaporization problem is not just a carb problem. That shiny bubble in the top of the sediment bowl is a bubble of gasoline vapor that I watched form and periodically burp on down the line and then reform, over and over, as the engine idled on a warm day. I tried many many things to fix it, including worrying that that oil filter was blocking cooling air from the fan, so I got an adpater that moved it out of the way.
I agree with those who point the finger at ethanol. But, it's not as simple as ethanol itself being low boiling. The problem is that neither gasoline nor ethanol are happy being together, so the vapor pressure of the mixture is raised as both try to get out (what, in the trade, is called a positive deviation from Raoult's Law). Modern cars cope with it by using fuel injectors and fuel pumps submerged in the gasoline tank that can keep things moving along.
This is a contentious subject that always reminds me a bit of PMS; those who have not personally had to deal with it are convinced that those who have are somehow making it all up. The problem is that two Model A's owned by the same guy running the same gas on the same day can have one vapor locking like mad and the other running like a top.
Steve