Not how it works or anything, just that it was a thing. When I took the carb off my intake I thought hmmm that's odd. That's when I started my limited education.
The PO of the truck said the carb needed work because it didn't run right when he parked it, some yrs back.
Someone somewhere sort of adapted a square bore carb to a spread bore. Anyway, I want it to run right. Adapter option? New intake option?
I don't have a plan as yet, other than the entire fuel system gets replaced. For now I thought this was humorous.

 

The intake is spreadbore. However that adapter is very much factory. There were no thermoquad carbs used on these engines in the states. It was either the Holley Square Bore or the Holley 4300 spreadbore used .

 

The adapter is simply the egr plate with the wrong gasket covering parts of the secondary ports. Then topped with what seems to me to be a really small square bore Holley. Definitely can't be factory ford?

Motor is allegedly the original 460 motor that was rebuilt at some point.

 

Thermoquads were spread bore carbs built with plastic body to better prevent heat soak or fuel boiling in the float bowls.

Many years ago, back in the '70s, I learned to apply a thin smearing of bearing grease to both sides of my carburetor gaskets so they "let go" of carb bases and intakes at next removal without peeling, usually they are re-useable even, and they seal good with the grease causing the gasket to not dry up.