69 vs 70 and 70 vs 71-2 455 Buick Fan Shrouds
by Dave Knutsen and George Nenadovich
The 70 NOS shroud is on top. They appear very similar though
and only the trained eye would be able to tell.
Lower mounting slots are wider apart on the 69
The upper mounting tabs are taller on the 70
The 1970 Big Block, 455, fan shroud for the Skylark GS models is
different than 1971-2 versions. As the photos show below, you can easily
tell the differences once you know what to look for when comparing fan shrouds.
This is a photo of the top of the shroud. A metal hose hook,
shaped like the letter "J", is attached to the shroud using two
screws. The hook keeps the upper radiator hose from contacting the fan blades.
This is a 1970 shroud with a smooth exterior surface. Notice
the entire perimeter of the circular portion is continous.
This is a 1972 455 shroud and it has a plastic hose hook.
This is a 1971-2 shroud in the same position as the 1970.
Notice here the circular portion has a small notch removed to clear the
power steering pump. Also notice, it has reinforcing ribs to keep the shroud
in the correct shape.
Here is a side-by-side comparison of the two shrouds. Differences
as discussed earlier are clearly evident. Also, notice the mounting points
for the 1971-2 (top shroud) is slightly offset to the front. The 1970 shroud
has the upper mounts flush with the leading edge of the shroud.
Duane Heckman states:
In 71 they changed the pulleys, water pump, engine accessory brackets,
as well as the fan (# of blades and diameter). So I guess that is why they
had to change the fan shroud. They also changed at least the upper radiator
hose, so the routing did not need the hook.
For 72 everything basically remained the same as 71, but because
of the air pump, a strap was needed to keep the upper hose where they wanted
it. And, even though the fan shroud retained the same shape, it was altered
by having the hole for the strap put in it, therefore it had a new part