[dhcarguy]

I need a new fan clutch. Can you guys recommend one for my 65 GTO, that is good or better than the OEM unit.?
Any brand names that sell quality fan clutches.
Are they all pretty much the same?

Thanks ,Dave

[PunchT37]

I believe the Hayden 2747 should fit. Not sure if Delco still makes fan clutches for these older cars. Most oem fans are electric now.

[leeklm]

They make three primary versions... standard, heavy duty, and severe duty/towing. Most people run the HD version shown here....

https://www.oreillyauto.com/detail/c...n+clutch&pos=0

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[RocktimusPryme]

There is some debate over the Sd or hd version but I third the Hayden.

The one thing I would add is that apparently most aftermarket fan clutches are set with something like 195-205 thermostats in mind. So if you want it to come on sooner you have to modify it. There is a thread in the cooling section about it.

[Joe's Garage]

It's the Heavy Duty version for most Pontiac V8s with clockwise rotation.

Rockauto sells them for $35.79 plus shipping and tax.

As noted, the HD and SD go full 'ON' at 195-205*, but we've also found that they slip significantly less when disengaged. So they're always pulling extra air - that's a good thing.

And the mod to make them kick in earlier is not that difficult. Youtube has several decent videos showing how to re-bend the thermostatic spring. Just be careful and take your time so you don't break it.

Good luck!

[FrankieT/A]

I forth the Hayden...

[lust4speed]

Since Hayden changed the specs of their heavy duty fan clutch there's not a whole lot of difference going up to the severe duty. They rate their fans on air temperature going over the fan clutch and they usually say it firms up at 175 or 180 degrees. My experience seems that that translates more to around 210° coolant temperature for advertised full engagement. As stated above the 2747 is the HD unit, and the severe duty unit is 2797. I still prefer the severe duty but that point can be argued. Both clutches have the same advertised specs and Hayden's explanation is the severe duty is for larger fans - but no explanation of their definition of "larger". The 19.5" seven blade fan qualifies in my book as large but maybe not theirs. Either clutch will cool much better with adjusting the thermal coil to have the fan come in earlier. My personal preference is to run a 160° thermostat and have the fan coming in around 185° coolant temperature.

[JSchmitz]

I've used both the heavy duty and severe duty clutches. Significant difference between the two. When the severe kicks in it's impressive. If you have marginal cooling I'd run the severe for sure.

[tempest1964]

If you read this thread, specifically post #31, but read it all. Mike Garblik did some research on fine tuning these clutchs so they kick in at the proper temperature. Thanks to Mike for this.
https://forums.maxperformanceinc.com...en#post6178042

[RocktimusPryme]

On the severe duty vs HD fan, I originally had a SD with an over the counter 18" 6 blade fan. It would not operate the clutch properly. If you arent at minimum running the big 7 blade 19" AC type fan, I wouldnt use the SD fan.

Also, many of us probably run later 11 bolt style pumps on pre 69 cars. This pushes your fan farther into your stock shroud. If you fit this bill, Hayden does make a shorter copy of the HD clutch to correct that. I cant remember the number off the top of my head but it isnt hard to find.

I switched to one of those.

[mgarblik]

As mentioned above, I did mess with the HD Hayden clutch some for my own application and based on a tech article in a Chevy magazine. I had some fitment issues on my 62 Catalina with a late model 11 bolt water pump. The SD clutch would have been too close to the radiator without a bunch of mods, so the HD unit was my choice. My car came with a 4 blade direct drive fan. I added a factory metal shroud and the clutch fan. Factory Hayden spring I modified slightly by trial and error to begin clutching at 175-180 degrees F. It doesn't take much to change it from the 195-200 degree range stock. I am happy with the results. So far, 200-205 is the very hottest the car has run with this set-up in 90 degree, slow moving traffic and sitting in traffic jams. The car does not have AC.

[joelau27]

Check Ames, or The Parts Place. They have the factory replacement looks almost exact.
The first one lasted over 50 yrs., I think the replacement will be fine.(I just put one in my '69.)

[David Jones]

I installed a Hayden HD in my car back in 2003. It's still on duty.

[70GS455]

Use the SD if your fan pitch is 2.5" or more

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[KEN CROCIE]

I have the Hayden on my '64 with the big 7 blade and on my chevy P/U . The Hd version. Both work great. I'm not fussy on engagement temp as long as the job gets done.