I have never heard of a BSA conrod in a 4G. If it was a good idea, I think I would have heard of it by now. I do know of Carillo rods being used but they needed the cranks re-balancing and I know that the man who did that has since passed on to a better place. At present I don't know of anyone who can re-balance Square Four cranks and one of the whole points of the new Club rods was to improve the balance by going back to the original weight of the (early) rods.
Ask yourself why these rods are cheap.
Stripping and rebuilding a Square Four engine is not a job most people would undertake lightly. If you use Club rods, the outcome is pretty well guaranteed to be good. If you use the BSA rods - who knows?
But whatever you do, make sure the crankshaft sludge traps are cleaned out or else whatever rod you choose will next be seen through the hole in the crankcase.
36 4G, 37 VH, 53 ex ISDT KHA (project), 54 KH(A), Healey 1000/4 (project)
Former Machine Registrar & Archivist, General Secretary and Single Spares Organiser.