What I remember on the 426 street Hemi pulleys is that the 1966 to 1968, maybe even some early 1969 cars had the first version which Mopar changed in 1969 to 1971 cars to the later pulleys I can't remember what the exact differences where now The 1964/1965 Race Hemi used a thin balancer like the 361/426W motors used with the straight timing tab timing covers. I think the later(1969/1971 Street Hemi) ones had a smaller diameter crank pulley As far as my statement on the water pump pulley I'm probally wrong on that now that I think about some of the standard steering (1962 to 1971) B/RB motors I have that there water pump pulleys might have work one or the other street Hemi motors