FUEL CAP---Help!!

[BlackBettyGMC]

I have a 1972 GMC with the 402bb. I am in need of the correct fuel cap that is vented.....Unless I'm doing something wrong. I bought a couple from LMC but my tank still has a great deal of pressure build up, not good. Does anyone have or know where I can get an NOS cap that is correct?
Thanks,
James

[cdowns]

72 the correct from the factory cap is non vented

the problem is probally // the vent line from the gastank that went up into the passenger side door frame then down into the frame and foward to the charcoal canister to carb// guys disconnect and just plug the lines causing a pressurized tank


if they had common sence and just left the vent line you would have no problem

[SS Tim]

If you are having an ongoing problem it does sound like the vent system itself is having a problem.
As you did not tell us what you actually have, 72 GMC covers a lot of metal and variations we are assuming you have a C1500.

Here are the drawings for a 72 chevy which are directly applicable to your truck if it is a C1500.

They are found in the factory service manual section 8.
If you don't have one they can be downloaded here.
http://67-72chevytrucks.com/vboard/s...d.php?t=558016

Remember if you are having a vent problem or smelling fuel it is most likely in the vent system and needs repairs or correction from a hack job improvement.