water pump for stock 455 driver

If you have the cash the TA cover is definitely the way to go. The 69 timing covers had smaller oil passages than the 71 and later so that is a plus. If you end up getting a new fan clutch forget the AC Delco model and step right up to the Hayden Severe Duty clutch and that baby will blow a hurricane when needed.

https://www.haydenauto.com/en/products/fan-clutches/fan-clutch-types/thermal

https://www.summitracing.com/parts/hda-2747/year/1972/make/buick/model/gs-455

 

Wow, thanks for that information!

The reason that I chose the AC Delco unit is, I also have a 2004, 2500 series Suburban LT with the 8.1 in it and 138,000 miles on it. When the original fan clutch was getting weak, I replaced it with a non-AC Delco unit that didn't last very long (I don't think it was a Hayden product though). Since then, I have been a big fan of using AC Delco parts, whenever available, on my GM vehicles.

 

My '95 Roadmaster wagon with tow package replacement clutch requires a Severe Duty unit and the Hayden#2747 shows up. Take a look at the AC Delco unit. Look suspiciously the same? Possibly your 8.1 needed a Severe Duty unit. All that extra beefy aluminum heatsinking is to dissipate heat.

https://www.summitracing.com/search...ick/model/roadmaster?N=part-type:fan-clutches

 

For those using the severe duty type fan clutches, they will need their cut in temp adjusted (lowered), as it is higher now.

 

Wondering what that means or how it would be done on a mechanical clutch?

 

There is a YouTube video on how, it's a simple procedure



Also some good info

https://www.chevelles.com/threads/adjusting-a-fan-clutch.389234/#post-3569369

Prob the best thread:

http://forums.maxperformanceinc.com/forums/showthread.php?p=6155375

 

Good info there about the tweaking. I could see where a higher start temp could be a problem with a 160* thermostat. I'd recommend running it as-is and get a refrence temperature before changing anything on the clutch. Get the car up to running temp and see where it starts to kick in(or not kick in).

Interesting too about how much lower the original factory temperature settings were. In my case I don't mind the engine running a little hotter when cruising around to keep the mileage up. Once they start to engage they will cool plenty. On my '65 GS w/455 that worked out well at the track. If the car was cooled off decent between rounds the clutch would disconnect after a few seconds of running time and be disconnected for a run. You really don't want any fan clutch to be locked up tight on a run because that fan is really blowing the air and soaking up the HP. For a hot climate cruiser I'd work with the tweaks if I didn't like the running temp.

I'm thinking any current AC Delco clutch made these days is pretty generic as far as the cut-in temp. Most emissions era vehicles would definitely want to see higher temps. My RMW runs around 195*(at the head,no less) pretty much most of the time, including towing a big load, so the fan clutch must be doing the job when necessary.

 

Thanks for posting up all the good information! When the time comes maybe I'll try the Hayden fan clutch.

After looking at a small stream of gear oil under the car last night, it appears that I'll be doing the pinion seal next... Ugh.

 

Larry, I'm pretty sure that the 1969 400 in my car has the short pump. This was something I had looked at when considering the replacement water pump.

Definitely a consideration for those with long pump big blocks though.

 

Thank you Larry!

 

The slick clutch setup would be something like the really modern cars have; mechanical fan with an electronically operated viscous clutch. If the mounting could be figured out, I could probably come up with the electronics (they have this large nut screw on type mounting, instead of the 4 studs).