page 68 of the 1967 engine equipment assembly manual shows what looks like a stamped steel crankshaft pulley, C4ME-6A301-A
a single groove add on pulley, same diameter as damper pulley, takes a 1/2" belt
+1 on the "AC" p/s pulley, it takes a 1/2" belt
the "AF" and the "AC" p/s pulleys are the same offset, but the "AF" pulley uses a 15/32" belt and is a larger diameter
which matches up when using the larger diameter crank pulleys (like C5AE-E)