The Rover-Landers of BC

Have a Marsland frame for an 88. The dimension between the tub mounts appears to be 3/4inch too long. If I move the tub aft to meet the rear tabs, the fuel tank fillers will not be in the tub flange. If I move the tub forward then there will be a lip at the rear that may interfere with the tailgate. Anybody had this problem?

I seem to recall that the factory manuals included detailed drawings with frame dimensions. Do you have access to a manual to use as a reference to confirm your suspicions?