buy a factroy manual if your going to keep da bike , with da kicker gears use da later 1971 up corse teeth not da early 1952 -70 clutch ratchet & mated thro out gears  , re bush every thing & shim up to spec,   pushrods are all da same ,pushrod  tubes are interchangeable1957 to 79 are cork 1980/1 up are rubber o ring can mix top & bottom just make sure you have da right seal  , tooo easy, any other ques on castiron sporty just fire away don't even have to look in da manual 

just looking at pushrods pic, are they alum push R's? if so was thinking when hot they will expand more that the cast iron heads?

all stock sporty cast iron pushrods are aluminium

try Redgraves for your part list ive been dealing with them for 30 yrs, yours a 1968 into a laste 1972 up frame , front brake  will need another disc & caliper is 1978 to 83 10 "twin  disc to stop proper