I’m not sure how your year of car was originally but it seems an odd place for the inlet. Is it the correct carburetor? If it is, maybe consider a right angle fitting right at the carburetor to minimize the section that is currently over the manifold. Also, my 1939 had a heat shield on the carburetor itself.

Then and now has good kits but the check valves are oversized too much so incredibly tight!

Thanks, Mal and Kev.

Mal - I do have the heat shield, but perhaps not enough of an arc of the fuel line routing.

I’m interested in the fuel filter as I can see how that could help this situation. Can you provide some details? Like this?
https://www.speedwaymotors.com/Glass-Bowl-Fuel-Filter,273099.html

Mal, that's also how the line on my 54 is routed as well. Also that glass filter right off the carb.

Fuel line on my long gone '41 120 proscribed a big arc from the fuel pump to the carb, keeping it well away from the exhaust manifold. In addition, the fuel pump had a heat shield protecting it. This photo illustrates both.

Maybe as a test, loosely crumple a ball of tin foil over the exposed metal portion of the fuel line and fitting at the carb.

Also, if you happen to have one of those laser thermometer doo-dads, keep checking the temp of thar area after you shut down the motor up to the point it starts to overflow.

There were some later carbs that had an auxiliary metal heatshield between the carb and the exposed manifold. Also later carbs had the fuel line come out the front of the carb and I to the glass bowl filter which usually always had a little air bubble in it. So that would have acted as buffer against pressure built up in the line.

The fact pressure is building up that is exceeding the fuel pump pressure and overcoming the float needle sure sounds like fuel is boiling in that line.

When the pump was just re-built and re-installed, a heat shield was installed that was previously not there. Also, the line was routed much better to be significantly farther away from the exhaust manifold. And, we split a rubber hose and put it over the line as additional insulation. That’s all part of what is so puzzling.




This is how it was previously.

Now and Then carries the kits:

https://www.then-now-auto.com/product-category/fuel-pump-kits/

Is it me or is the gasket area on that pan also warped from over-torquing?

Looks like they supported it with a bottle jack...?

It's a Lark-Up!