I have a 4160 on a '67 Mustang 289 installed in 2015 and it did sit a lot from time to time. Been after what seemed to be vapor lock issues. Replaced ALL fuel components and added Holley Mighty Mite pump at the tank, but still stalls if you drive too hard or uphill. Today when the bowl emptied after a medium drive, I decided to crack the float screw. Nothing came out. I cracked the rear float screw and sure enough it sprayed quite a bit. So I removed the whole float screw and valve. I gave it a crank and I could see gas slowly begin to circulate. I put it back together and cranked some more and eventually the bowl filled and I got it home. Before I rip into it, what could this be? Clogged inlet? Something stuck from the few years of sitting? I have a rebuild kit ready to go but I’d like to know what I should look for. Thanks for any input.