David You did not mention it but that is one of the first versions of the Spence Wolf/Cupertino bike shop long arm derailleurs. Mafacs were also a Spence favorite plus the TA crankset. This bike says Cupertino bike shop . BOB FREITAS MILL VALLEY,CA USA
today someone mentioned using the upper pivot assembly from a Campagnolo Sport rear derailleur to hot rod a Gran Sport or Record derailleur,Spence Wolf also used this modification for his long arm conversions, that is my plan as I now have all the various parts needed