I get scared when folks talk about using brake cleaner to check for vacuum leaks. Some kinds of brake cleaner aren't flammable, they'll make no difference when sucked into the intake stream. Other kinds create phosgene gas when burned, which is very poisonous.I usually use pb blaster,or brake kleen flammable brake parts cleaner because that's what I have on hand,
I use aerosol carburetor cleaner.
TBI 305 and TBI 350 use essentially the same fuel pressure. The injectors have higher flow on the 350 vs. 305.if this turns out to be a 305 tbi not off a 350 then the regulator spring is probably wrong pressure as well