1949 BSA Gold Star crankcase matching set.  Hard-used competition engine with expert weld repairs, now requiring machine work including line boring the main bearings and seating the cam spindles.  These cases are sound and definitely restorable.  Cosmetic repairs at discretion of buyer. The serial number has not been altered.These ZBGS engines are scarce and sought after.  I do have other parts but not the alloy cylinder or head or crank.This engine came on a much-modified off-road racer with a later BSA swing arm frame from New Mexico, bought on eBay 12 years ago. If upon receipt of these parts you wish to return them please contact me within 4 weeks of receipt.