Vapor Lock question

Petty Blu 72 said
After a short drive, say 3-5 miles. I open the gas cap and get quite a lot of air rushing in the tank. Could I soon get vapor lock? Why is the cap not allowing air to replace gas? Could it be plugged? Is there a way to check it?
Should I drill a small pin hole in the cap to allow air to come in tank?
Any thoughts?:glasses7:

ntsqd said
Shouldn't a car of that era have a simple tank vent? The vent on my'65.

Somehow I got the impression we were talking about a 65? Then I look at your screen name??????????? So what, a 72?................................?

This is a different animal. This originally had the evaporative emissions 'stuff' and a so called "pressure vacuum" cap. Have you modified the tank system? What did you do with the 1/4" line coming up to the front?

How it works is in the shop manual:

http://www.forabodiesonly.com/mopar/showthread.php?t=244981

http://www.forabodiesonly.com/mopar/showthread.php?p=1969591363

http://www.forabodiesonly.com/mopar/showthread.php?t=183956