ok on a 84 camaro 305 what size are the fuel lines please hurry im about to go pick some up.

 

3/8" on the feed side, 5/16" on the bypass/return side (if your car is equipped with a bypass-style mechanical fuel pump). This is easy to tell becuase the bypass style pumps have 3 lines coming off of them. 1 feed line from the tank (3/8), 1 line to the carb (3/8) and 1 bypass/return line back to the tank (5/16).

If you are using an aftermarket fuel pump it will not have the bypass/retun line fitting. Just plug the factory bypass/return line and run without it. It won't do any harm or cause any ill effects.