Rusted out sending unit lines?
Rotted steel lines from pump to carb?
Dry rotted rubber lines down at the pump?
Leaking carb seals?
Charcoal canister vent lines cracked broken?
Start car and let it idle. Sniff around.... Smell stronger up in the engine or at the back of the car?
Anything wet under the hood? Especially at the carb?
Don't mess around when it comes to fuel smells.... I've seen a few old skool carb'd cars go up in flames from leaking gas.