Dan,
Was the truck running before you cut the hose? Are you sure there is gas in the tank or line? If this was a non running truck that's been sitting awhile, it's either dry empty or plugged with gunk -- probably both.
I have a '65, and I helped hamiatjax with his '62 and I didn't see any kind of valve on either one. And even if it had a one way valve, it would certainly allow fuel to run out from the tank (assuming there was any fuel in the tank to begin with).
You might also try asking this question in the 60-66 Forum.
Good luck,
John
