I have a 70 elcamino 502 big block comp 280h cam, 850 double pumper, roller rockers, mallory electric fuel pump,carb has been rebuilt, also once in a while fuel comes out of front vent on carb ive noticed when cold it runs about 6 to 7 psi fuel pressure when hot fuel pressure drops to 3 or below when i shut off car fuel drips near tank out the gasoline neck when i take off cap fuel spills out, the vent hose was capped off with a screw so i removed it, now gas comes out vent hose after driving it helpppppppp

Don't have a clue, sorry. Thought I would tell you to reference this post in chevelle tech, you will get much greater visibility, not as many people seem to come to this forum.