I have a pulley problem. On my 304 the crankshaft pulley had two chips missing on the inner wall(closest to the engine). I bought a used replacement and it looked different, but I figured it was OK. Everything was fine until I put the water pump pulley on, or tried to. The replacement turns out to be 1/4" bigger in diameter, and so won't fit (the w.p. pulley hits the c.s. pulley). Mine and the replacement are both for AMC 304's/360's.
Are there different matched sets, or something? My pulley is heavy, has a thick backplate and three dimples. The replacement is much lighter.