Cooling Fan Question.

[Pacecarjeff]

I have seen that all of the early Chevrolets used the short water Pump through 1968 (except Corvette = through 1972) They all used a fan with 3" bolt spacing. Now I find out from some that the 67-8 Z/28, as well as the L-78 used the later 3.25" spacing.
That is the spacing used for the later "long" water pumps.
Are the water pumps different on those 2 67-8 Chevy applications, as to use a differnt fan and clutch.

I know that all the other motor divisions used the larger spacing, and Chevy was different. Why were these 2 applications different then the rest of the Chevrolet engine line?

[Pacecarjeff]

All the information was on the CRG site.
I am all clear on this.

Look here: http://www.camaros.org/coolingsystems.shtml
CRG Research Report - 1967-69 Cooling Systems

[Steve Shauger]

I believe the clutches were different, due to the high rpm range and performance application of the L78 and Z28.

[Pacecarjeff]

Yes, the clutches would have to be different in order to fit.
I would imagine they are VERY rare.

This is unusual that the fans and clutches are different from the Corvettes - all the 427's, even the L88, and L89 cars used the 3" spacing. Wonder why GM felt those 396's and 302's needed something different?