So to get a handle on this I actually bought from a junkyard 2 lock ring sections cut from old gas tanks. The first, a 72 B body I think, had an O RING. I didn't know those had o rings instead of flat seals. Can anyone confirm they have seen o-rings and what year model?

Also I'd be interested in the thickness of your old flat seal. Seems like they varied from .062 to .093".

Also can anyone confirm the thickness of the lock rings. Those obviously varied too. The 2 I have from a 72 and a 68 B body are both .050" but I know I've measured a .080" thick one before.

I'd Paypal a few $ for a picture and a measurement.

Thanks!