I have to agree with what Markos says in regard to the desirability of corresponding engine and chassis numbers. I think that this derives from european trends, particularly in British motorcycles, where a non-matching machine will never command the same price at auction as an original. Take Vincents, for example, where all the major engine and gearbox castings are stamped with a unique reference (sometimes mating) number. The frame number to the upper frame member should match the number on the rear swinging-arm and the engine number is almost invariably found to be 1900 digits away. You can imagine that this is fertile ground for obsessional people who would readily turn their noses up in the event of any inconsistency being apparent. More and more I note advertisements for classic cars following the same trend. I know...I know! Best wishes, John.