fuel tank installation?

[Torque]

The one original fuel tank I have has a ring screwed on the outside of the filler neck. What is this ring for? Does it screw on after you install the cover to lock the tank to keep it form moving or does the ring go under the cover?
  My repo tank is also threaded for this ring, anyone have a source for them? or do I need it?  Thanks

[steve-0]

it looks like to me that the original tanks where insulated then the ring was screwed on to seal that area of the tank.
it was not installed over the cover..

if you have an original ring to screw on your tank it will look better under the cover since the guard hole OD and your repo tank neck will leave a gap. I'm assuming an original ring will fit . I repo'd my own tanks.

http://halftrackinfo.com/index.php?topic=884.15

[Torque]

Thanks Steve, that explains it.