Your bike has probably had the engine replaced at some stage like 99.9% of Scott’s have. These engines need to be built properly and if they are not they will self destruct very quickly as was often the case when thrashed in use. There are only around ten left with matching numbers but there are oddities such as the crankcase currently fitted to my ’27 flyer; its a 27/28 crankcase but the number indicates 1939 manufacture!
The engine you have is not far off number wise to my 27’s long lost (or blown up) original while your frame number is perhaps a little high for 1929 given that my other project bike is in the 3***m series (reg’d for the road May 1930) but there was no order to the frame numbers as bikes were despatched by their engine number unlike any other company!
Not being matching numbers does not make it any less usable so get out there and smoke the four-wheeled tin box drivers out!