1969 427/390 Fan Clutch

[Salvatore I.]

In need of some guidance in locating a correct, dated fan clutch for a 1969 427/390 engine or a lead on a supplier who can correctly rebuild my existing fan clutch that is on the car.....

How can I tell if the one on the car is the original and not a replacement?

The advice is appreciated!

[Joe L.]

Re: 1969 427/390 Fan Clutch

Sal-----

Well, the very first thing to check is the fan clutch mounting flange (where it "bolts up" to the pulley). If the flange has SLOTS instead of HOLES, then you need check no further----you have an aftermarket, replacement fan clutch.

Otherwise, the fan clutch originally used for your application was GM #3937771. It's also possible that other clutches were used, but this is the most likely. These clutches usually have a date stamped on them on the periphery of the mounting flange, so, if you have an otherwise correct clutch, that will tell you if it may be original to the car or a later replacement.

A photo of the face of a GM #3937771 is seen below.

[Joe L.]

Re: 1969 427/390 Fan Clutch

Sal-----

Well, the very first thing to check is the fan clutch mounting flange (where it "bolts up" to the pulley). If the flange has SLOTS instead of HOLES, then you need check no further----you have an aftermarket, replacement fan clutch.

Otherwise, the fan clutch originally used for your application was GM #3937771. It's also possible that other clutches were used, but this is the most likely. These clutches usually have a date stamped on them on the periphery of the mounting flange, so, if you have an otherwise correct clutch, that will tell you if it may be original to the car or a later replacement.

A photo of the face of a GM #3937771 is seen below.

[Henry A.]

Re: 1969 427/390 Fan Clutch

I have one...that is dated 1 28 67. This may be to early, but may work.

[Henry A.]

Re: 1969 427/390 Fan Clutch

I have one...that is dated 1 28 67. This may be to early, but may work.