[78 WS6]

I am seeking a advice on a replacement water pump for my 78 WS6.

THANX!

[steve25]

Ames performance has a nice one with the right/ good cast impeller.
You could also send yours out and get it rebuilt if your ok with laying the car up for a month.

['ol Pinion head]

If its not the original casting & date range, have several late '77 casting pumps in stock. Have one late '77 pump fresh rebuilt, as always with the correct cast impeller. Its slated for a '79 PWH engine build, but that may not happen til April. Also have another rebuild session going after the first of the year.

[ponyakr]

Unless you want original iron, you can buy an alum Flowkooler or PRW.

https://www.summitracing.com/parts/bra-1649/overview/

https://www.ebay.com/itm/PRW-1445500...-/380526071479

Edelbrock has a really high dollar model, and GMB has a cheap one.

https://www.summitracing.com/parts/edl-8856/overview/

https://www.summitracing.com/parts/g...80al/overview/

[dataway]

I just bought a "Gates" pump for my 68, very nice piece, cast impeller too. From Rock Auto.

[78 WS6]

Originally Posted by 'ol Pinion head

If its not the original casting & date range, have several late '77 casting pumps in stock. Have one late '77 pump fresh rebuilt, as always with the correct cast impeller. Its slated for a '79 PWH engine build, but that may not happen til April. Also have another rebuild session going after the first of the year.

I have the OEM off to replace timing cover. It only has about 80K on it, but it would seem to be prudent to replace/rebuild at this time. On my numerous Chevys I have always used Stewart but they don't do Pontiac.

[dataway]

Get OPH to rebuild the original, better than any aftermarket pump.

[STEELCITYFIREBIRD]

Are you looking for #'s correct pump, or a pump that will do the job well?

[77 TRASHCAN]

I had a GMB on my car, bearing pooped after 2000 miles, not something I'll use again.

[STEELCITYFIREBIRD]

Well, I just received a GMB aluminum pump, I hope it lasts..... might take a while before I get 2000 miles on my car to evaluate the quality of this product.

Anyone else have a good or bad experience with GMB pumps?

[ponyakr]

I thought the first review of the Milodon pump, on the Summit site, was very interesting. The guy says the Milodon is just a reboxed GMB.

https://www.summitracing.com/parts/m...w/make/pontiac

https://www.summitracing.com/parts/g...RoCO80QAvD_BwE

[STEELCITYFIREBIRD]

I await getting home today to see what style impeller it has.

[78 WS6]

Originally Posted by 77 TRASHCAN

I had a GMB on my car, bearing pooped after 2000 miles, not something I'll use again.

I see where GMB has multiple pumps available, which one did you try?

[77 TRASHCAN]

Originally Posted by 78 WS6

I see where GMB has multiple pumps available, which one did you try?

Not sure. There was likely just one available for my 77 T/A (11 bolt, original) when I purchased it.

I worked at an auto parts store from 1985-1998. Somewhere in that time we had a line of strictly "new" import water pumps. I ordered a Pontiac, was surprised it was aluminum. Thinking I'd found an affordable aluminum water pump. So much for a bargain...
The life span on Mine went for several years, because, I seldom drove the car, as you intrend to with yours...
I sold another one of those exact pumps to a friend with a 70 GTO. His car saw more driving time. Seemed like about a years time on his before it crapped out.

I was in a hurry when the aluminum pump gave out.
I bought a "New" AC Delco pump. It was an iron pump with the stamped impeller. I adjusted the seperater plate for absolute minimum clearance. This pump was the 4th one I had installed. TIt was the 4th because, when I performed other engine repairs/modifications in that area, I replaced the pump, preventatively.
The iron pump with the modified plate cooled the engine exactly as cool as the O.E. pump. Man, wish I'd kept the O. E. pump. The other pumps had no cooling issues, just ran slightly warmer...

['ol Pinion head]

One thing learned many years ago is many of the '77-81 Pontiac v8 water pumps originally used a "296" pump with a cast impeller with abbreviated fins. The slightly shorter fins worked fine in even in my modded Turbo 301, this design impeller also has slightly less drag. That particular style impeller also works well in a street/strip type engine that the block has had its coolant capacity reduced by a short fill of hard block.

On a normal 400-455 11bolt pump cooling deal, like a W72 400, am not rebuilding with that impeller, but using the correct full length cast impeller. Pontiac used at least 5 different cast impellers in original V8 waterpumps from '63-81. they designed the original pumps to match cooling system's needs, and as time progressed, introduced cooling system refinements. As Tom V likes to note "Engineers do things for a reason"! For many cooling applucations, its very hard to beat a correct design cast impeller waterpump. The majority of original Pontiac cores I have are '64-73 range, some of the early casting numbers are getting very very hard to come up with. With the interest in '77-79 400 models, have dug out more of that date range pump cores & am rebuilding upon need.

[pippintook]

Getting an OEM waterpump rebuilt is a good idea. The factory waterpumps and their nice cast impellers are good quality. I was in a pinch when I replaced my waterpump - so, I used the Napa TruFlow waterpump #41302. I think this is the same as the Gates #43102. This is a new pump (not too pricey) and I thought it has decent cast impellers that are a little shorter than factory. If using a non OEM pump (maybe OEM too?) I think it is a good idea to check your clearance between the divider plate and your impeller. I adjusted my divider plate slightly to get better clearance - this thread has details http://forums.maxperformanceinc.com/...d.php?t=411256

[Daubert20]

I figured I would add my latest experience to this older post for those looking for info on water pumps. I just bought a NAPA TFW 43102 pump. The pic online shows a cast impeller but the pump I got yesterday (12/28/2021) has a stamped steel one. A test fit with my new Ames ss divider plate shows about a 1/4" of clearance. (The new divider plate fits nice against my old pump with the cast impeller.)

Too bad, this was one of the pumps that was a good option.

[big matt]

I chucked a duralast one from autozone on pontiac 350 a week ago. It was new, lifetime warranty, and $42. I ordered it in am, it was there 2 hrs later. Came with gaskets, no divider. I had a new one on the shelf. It has a cast impeller, and seemed minty. Time will tell. If it dies, i go grab another on the house

[Daubert20]

I got a Dayco DP836 from RockAuto. It has a cast impeller (like the image on the website) and has the same clearance with my new divider plate as my old pump and divider which I had in the car for the last 25years.

[78w72]

im a little late to this thread, but as mentioned if original isnt a concern i use & like the PRW aluminum pump. it has a cast impeller but the vanes have been machined to a cleaner shape, not sure what the benefit of that is but they felt it was worth it to do as opposed to just leaving them rough cast. it also was very close to the divider plate & only required minimal effort to get a tighter clearance. i run a 467 E-head stroker with only a budget 3 row alum radiator & the car runs at 180-190 in all situations from hot summer street driving to drag racing.

anyone have opinions on the machined vanes?

https://butlerperformance.com/i-3164...w-1445500.html