Well the plate on the neck says 74 but the title says 75
the engine says:

CB750E-2403954

so if I am looking at the chart correctly then it should be

750K5 1975 . 341 CB750-2500001 - CB750E-2372115 -
If I am wrong please let me know.

SystemFailure thanks for the link those are cheap compared to what I was looking at.