I have the same problem in my '85 Westy.  Investigation revealed that someone
in the dim past used the gas tank supports as floor lift resting points.  The
supports are bent upward and the gas tank is bent upward as well.  I suspect
the capacity is reduced somewhat, but the most serious problem is that
unsuspecting drivers run out of gas prematurely because the tank is empty when
the guage needle hits the red area on the guage.  May check to see if the tank
is intact.

Tom
Bloomington, IL
'85 Westy

[message/rfc822]