Often times, removing the PV will slightly improve the “hit” on the line.

I’d take it out and see what happens........ easy enough to put it back in.

Do the OE bowls have site plugs?
If not, I’m guessing the floats are a little too high, and/or the fuel pressure is slightly too high.

Holes in all 4 butterflies?
Better check the wording on that in the rules.

We had an issue with that years ago.
We had to replace the rear blades(with some that had no holes) before we could continue running, and they disallowed our qualifying runs.

An easy test is lift the carb off the manifold an inch or so, and block it up with something.
Turn on the fuel pump and see if any fuel starts dripping from anywhere underneath.
I’ve seen fuel dripping out from places where it theoretically “couldn’t”.