Try this for gasoline-

https://www.pure-gas.org/

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"Steel gaskets?  You sure?"

It must be those combination fiber/steel mesh like gaskets.    

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"Do they sell stock material that you can cut yourself. Should I make these as thick as possible to fit under hood? Maybe 1, 2, or 3". I do have room."

Yes, they sell sheet stock if you want to make your own. Usually, you want just 1/4" as raising the spacer height may play with plenum volume.

Here is a set of store bought - https://www.dashman.net/product.html?id=207

Just isolate the problem before throwing money at it. I don't want you to get mad at me.

Did you say you have an inline filter before the mechanical pump? What micron size?

What is the application, a pickup with a "292"?

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Did anyone pick this up from the first post
"Does restart with foot to the floor and engine recovers and idles normal after a minute or so"

It's not starving for fuel, it's flooding most likely from fuel boiling in the bowls. insulated carb spacers may help.