72 BB with AC

[Melissa N.]

Does the fan clutch for a 72 BB AC car differ from the clutch for a SB or non-AC car? If so, how do I distinguish the correct clutch. The judging manual reads as if the clutch is the same for BB's and SB's and AC and non-AC.
Thanks for any responses.

[Joe L.]

Re: 72 BB with AC

Melissa-----

GM says that only 1 fan clutch was used for 1972 Corvettes regardless of engine or with/without A/C. That fan clutch was a GM #3991426. I'm not 100% certain regarding the configuration of this clutch. However, I believe that it was a Sweitzer-manufactured clutch with a "bi-metallic", rectangular thermostat. Also, I believe that it had a pie-pan like extension around the perimeter of the "vaned" central portion of the clutch. Like all 1971+ Corvette fan clutches, it used the 3/4" waterpump shaft pilot hole and the 2-1/8" bolt circle hub mounting pattern with holes and NOT slots.

[Jack H.]

Add on...

There's a virtually identical 7-inch fan clutch out there also made by Schwitzer that's easy to confuse with the Chevy/Corvette version. The difference lies in the height of the cooling fins on the center face. The Corvette version has tall cooling fins (almost the same height as the outer ring of the housing) while the 'look alike' clutch has shorter cooling fins that fall short of the outer ring plane by approximately 1/2-inch...