quick carburetor question

[69mach351]

Hello again, my 4 barrel Holley carburetor is leaking gas out of a hole in the bottom ( not in the barrel, just outside the barrel on the side of the two primaries.) Is this normal? At the end of the day the gas in the primarie float bowl gets very low. Also, if I buy a new 4v carburetor, what is the best size if I have a 351W? I intend to make it an everyday driver, and don't intend to do much heavy road-racing. Thanks so much for any help. I am stuck right now so I would be grateful for any imput....David Bridwell

p.s. I don't know what size carb I have now, I took it to parts stores, and looked in a Holley book but the number is not listed.
(80508 3176) (R-6931)