Saginaw 4 speeds were out of production by 1977, and Vettes never used them anyway. They were used in Vegas, Camaros, Chevelles etc, usually behind L6 motors but with some small V8s too. Get a catalog from
Patrick\'s - it has all the ID info on finding the right Saginaw. The going price for a decent Sag 4-speed in these parts is about $150 tops.