My 1971 Stingray 350 cu. has a vented gas cap i believe and there is no rubber washer on it. I'm thinking that's why my garage smells of fuel so much! I bought a Non-Vented gas cap for my year Corvette from Ecklers, but why is there two choices of vented to Non-vented? Will it hurt my car if I put the Non-vented gas cap on which has the black O ring or Washer already? Thanks guys! Ed

You can't use the non-vented cap if your car was designed for the vented type. Joel or someone else will tell you what 71 came with.

Not sure off the top o me haid which ones had the vented caps....some did, some dint, in those years. Using a Non-vented cap where it requires a Vented cap is not a good idea, tho....the tank needs some sort of vent. "Sealed", or non-vented tanks were vented thru the vapor recovery system. A non-vented cap on a "vented" system can cause the tank to cave in, and can cause fuel starvation if the fuel pump pulls a vacuum on the tank while driving. It's best to replace the cap with the same type the system was designed for...and one with a gasket on it. The missing gasket is prolly the main reason for the fumes. I would need to research it a little to find out which cars had what, unless someone else has a definitive answer.

I finally had time to do a little research, and here's what I found.
'63-'69 used Vented caps.
'70'72 had Sealed, or non-vented caps. (The 71 cars had a red plastic plate on the fuel cap with white lettering stating "Open Slowly- Caution".)

So...your car SHOULD have a NON-vented/Sealed cap.

You should check if your vapor canister is still connected . If the hose from the fuel tank to the canister has been capped you will need a vented gas cap.