['ol Pinion head]

Little more complicated than just water pump heights, esp if pulleys have been mismatched. In comparing water pumps, also need to compare the thickness of the timing cvers they attach to...

The '64-65, 66, 67, & 68 timing cover is aprox 2 11/16" thick & with waterpump mounted, there is a distance of aprox 6 1/2" from block mating surface to w/p pulley mating flange.

The '69 & later timing cover is aprox 2" thick & with water pump mounted, distance is aprox 7" from block mating surface to w/p pulley mating flange.

Often the question is brought up..."Which balancer, which timing cover, which pulleys?"

IF, one is doing a high point resto & has to run 64, 65, or (thicker groove) '66 water pump pulleys along with '66 & earlier p/s pump set-up, it is smart to retain early style timing cover, have original balancer rebuilt, & use '64-68 waterpump.

If one wants to do away with expensive early timing covers & troublesome balancers, one can use common GM '68+ balancer (or aftermarket version). To do so one will use '69+ timing cover, '68-70 lower pulley(s), plus '69-70 (exc '70 1/2 V8 Firebird) waterpump pulley. This will work on '64-68 cars, one just gives up some originality in appearance on the '64-66's. '67 can retain '67-70 powersteering pump & brackets, & many will be fooled that set-up is not stock, until they notice the '68+ style balancer.

Hope this helps.