BMorgil mentions fuel pressure. About half of folks find that new fuel pumps will develop more pressure than the float/needle combination will effectively regulate.

You can reduce fuel pump pressure by adding a spacer between the pump and the block, but another option is to add a regulator to the fuel line between the pump and carburetor. The '48 tended to overfill and flood, with several carburetors, until I added a regulator.

I set it to 2 1/2 PSI and it has worked like a charm ever since - but you may not need one.

https://www.autozone.com/fuel-system...DacyTWYtr3TDnY

Good Luck and keep us informed on what's happening.