Fan
holes are 1 11/16 apart, center to center, when
measured along the "sides" of the flange (not measured
diagonally over the center). You can also measure the
"right side" of one hole to the "right side" of the
next hole if that is easier then trying to see the
"center" of the holes. If you have the pulley off, the
bolt pattern is easier to measure than using the
pump
Flange
height (distance from backside of rear plate to flange
surface that pulley rides on is 4 9/16 inches. It
takes a single groove pulley.
This
was designed to work with a 2-piece metal fan. Only
the 68-70 pumps were designed to have a 1 inch spacer
block behind the water pump and a 1" spacer block (to
replace the defective fan clutches) between the pulley
and the fan.
After
35+ years your car could have almost anything cobbled
up to work on it. This is a correct part for a USA
63-67 1/2 roadster. (Or at least these
specifications...) There are lots of different pumps
as this engine was used in other applications. Using
the newer style pumps present problems as the radiator
(and its location), fan shroud, fan, pulley,
alternator, alternator brackets, radiator hoses
alternator location, and crank pulley were different
as well.
Sometimes
engines get swapped by owners or mechanics that don't
know the differences in or have access to all the
auxiliary parts. The changeover to the 68 -70 parts
happened at approximately engine #R 58000
