Fits every A series engine from 1959-1996 (except twin point injection minis)
they have a different switch
GPS135 and also have a transducer for oil temperature (
YCB100320).
These original type oil switches came on when oil pressure dropped below 7-10lbs
but if you require earlier warning than that then use
HPS1 which activates at about 22lb or
HPS3 which is adjustable from 15-60lb.