We're working on an English 35 with the Standard 23C diesel engine. Tractor serial 159XXX. The flywheel ON the tractor has a step of 1.297(I measured) to 1.303 (buddy measured), and it has no evidence of being machined after production. There is no casting number on the flywheel. The clutch kits available are for 1.140" step(for up to serial 177394), or 1.720" (for serial 177538 up), and neither when test installed were able to be adjusted to work. Has anybody else come across this problem and have a solution? Like a dummy I sent the clutch core back before the engine was done so we can't use it for comparison. Will a flywheel off a Perkins 3.152 bolt up? Different PART number, and no casting number on this one to compare.