Basic if robust engine in pre-war chassis until ’49 when plunger back end was fitted. Even after a swinging arm was fitted in ’54, handling remained weird above 60mph. Best one’s the A10 inspired duplex frame used in the last four years of production. Strong bottom end but poor starting, gearbox and valvegear. Gold Star’s tuned B31 mill in better chassis; rorty but far too expensive. Plenty of usable B31’s with sensible mod’s.