Current Projects chat and miscellany

got a 50s falcon, 5 speed casette and 1 chainring, i have the chain, which is slightly different to any single speed or geared chain i've seen before, in shape and dimensions.
the bike needs new crankset/chainring, anyone know what size chain it might be?

Pics?

If you're replacing the cranks and chain ring then you may as well switch the screw on block, no?

Depending on the set up you might also be able to switch to a 6/7 speed. If the Shifter is friction there's a good chance it'll work (I think).