Reply to "Rear hub adjustment"

As Larry Finch mentioned, factory GT-5 and GT5-S cars with giant rear wheels used a variety of different inner bearings. The latest I've seen is in an '87 which used a std ball on the outer position and a straight roller bearing of the same OD for the inner bearing (the upright was bored out), with a severely shortened inner spacer. Euro GTS and Gr-3 club racers used double-row ball bearings inboard and here, the small diameter inner bearing bore was not enlarged but the spacer was only shortened. Note that this was for "only" 10" wide rear wheels, and the double wide bearing gets pushed inboard a little so it hangs over the cast-in relief in the middle of the upright, thus a small part of the bearing race is sort of unsupported. This looks bad but apparently caused no problems in the factory cars mentioned. A local machine shop should be able to bore your inner bearing bore out in your carriers to accept the large straight rollers, since its only a slip-fit.
Note also that the problem is NOT with the bearings: the stock axles were fabricated 0.0005" undersized at the factory for some odd reason, which took away the required press-fit. Then with corenering loads, 300+ bhp and frictional heat, the soft axles began fretting in the extremely hard bearing races, wearing away the axles. Wilkinson's current replacement axles restores the needed press-fit and are made of better steel (EN-36) than OEM, fixing both problems.