I pulled my 305 out of my 82 ta and along with it, the emissions controls, among those the charcol canister. I was told if you take this out you need a vented gas cap, since this provides the venting? if this is true what is the seperate line coming from my tank and has (what looks to be) a check valve and it just hangs above the rearend? any help?

 

That's a relief valve. It lets excessive pressure out, not air in.

 

I figured it was something along those lines, how about needing a vented cap?

 

Yes you will need one. Unless you don't plug that line that went to the charcoal canister (which is foolish not to if you removed it anyway). Like five7kid said, as the fuel pump sucks fuel out of the tank, a low pressure area is generated in the tank, so in order for it to equalize in pressure (to keep your car running), you'll need to let air in some way. The vented gas cap is your answer.

 

I'm trying to find a vented cap (perferably a locking one) for my 82. question are all the caps 82-02 the same (threads)? becasue at my local stores they only have locking NON vented, wondering if I should tell them various years to find what I need. thanks