70 454 Cooling Fan with A/C

[Mark #28455]

be careful, Ford had one too!

I bought a "Corvette" fan clutch from a certain well known chap in Chicago only to see a Ford date/part code stamped on the flange where the usual date code should have been. The bolt circle was correct as was the pilot hole, but the input shaft was a little longer than the stock Corvette piece.

Make sure to ask about the date code!

Mark

[Carr C.]

Re: 70 454 with A/C - water pump and fan clutch?

The pictures give me an idea of what I'm looking for, thanks Joe.

Now I just need to find one for a B19 built '70 454 w/ A/C.

Any ideas?

[Jack H.]

Also used on SB cars...

The '771 fan clutch was installed on 1971 SB Corvettes when they were A/C equipped, so there are other sources for the beast. When shopping about beware of this part's 'look alike' cousin! You'll find a virtually identical Schwitzer 7-inch clutch used on other cars & trucks of the era with the difference being the height of the cooling fins surrounding the actuator bar on the face of the clutch.

The '771 clutch has TALL cooling fins which stand up almost to the level of the housing's front outer ring. The 'look alike' clutch has shorter cooling fins and they stop about 3/8-inch short of the plane of the housing's outer ring....

[Joe L.]

Re: Also used on SB cars...

Jack-----

I don't see how the GM #3937771 fan clutch could have been used for any 1971 Corvettes. 1971 changed to the "large" hub mounting pattern and used a 3/4" pilot. The 3/4" pilot, alone, would have prevented the use of the 3937771 fan clutch on a 1971.

While the AIM may show the 3937771 fan clutch as having been used for 1971 small block with C-60 applications, I believe that's an error. For one thing, the AIM also shows that the fan used as being a GM #3991427. However, the GM #3991427 fan would not even bolt up to a GM #3937771 fan clutch. Absolutely impossible to mount these components together.