Slant Six Identification Help?!?!?!

64Lucy, in fact all slant-6 water pumps are interchangeable. There is no year cutoff at 1975. The 170 engine used a different water pump in 1960 only—it had a 3¼" diameter impeller, while the 225 had a 3½" impeller. For 1961 this was commonized to the 3½" impeller, which is compatible with the 1960 170 engine.