Which impeller is the stock style cast OEM (pics included)?
 

Okay...after trying to read through the mega thread and archives, finally decided to just post some pics to get the correct answer about the cast impeller style/fins.

Some of the old threads don't really pinpoint which style is the correct one, so here goes...I am assuming the NAPA/GMP design.

NAPA - (aluminum body) - https://www.napaonline.com/en/p/TWQN...put=water+pump
https://media.napaonline.com/is/imag...pany/139822343

GMP - from Summit - https://www.summitracing.com/parts/g...tiac/model/gto
https://static.summitracing.com/glob....jpg?rep=False

Cardone
https://www.cardone.com/UserFiles/Im...lef_Medium.jpg

Autozone - (with limited lifetime warranty) similar design as Cardone - https://www.autozone.com/cooling-hea...87_0?rrec=true
https://contentinfo.autozone.com/zne...411/2/image/3/

Napa and GMP are cast.
Cardone and Autozone are stamped steel

Both cast are not full vane like GM had designed , the ones posted are the 301 engine design.

Does anyone sell the original GM design? I've only found the two designs...

Here's what the cast one from my stock motor looks like. https://uploads.tapatalk-cdn.com/202...8c95e54f4e.jpghttps://uploads.tapatalk-cdn.com/202...66e313f7bb.jpg

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Try Gates. Their 43102 for the 11 bolt pump lists the impeller material as cast iron. The pics are of a Gates that I bought for my 8 bolt pump. The vanes look like the correct OEM pump vanes posted above. The hub also only has four mounting holes like OEM, not the 8 or so that a lot of the aftermarkets have. Yes, the pump is made in China but Gates has a good warranty and it appears to be quality made. As previously stated, almost every reman or new cheapie pump is going to have the cheap stamped steel impeller.

There were at least 5 different factory design cast impellers used on late '63-81 Pontiac waterpumps.

-abbreviated style impeller used on '64 & 65 8 bolt pumps.
-longer vane impellers used on '66-68 8 bolt pumps
-early shallow recess impellers used on the first 11 bolt pumps
-late deeper recess impellers on the last casting of 11 bolt pumps
-abbreviated vane used on 301 & 265 pumps (utilized as the hard block 400-455 impeller)

-John V has mentioned an even less drag (shorter height vane) cast impeller used in a '63 Tempest 4cyl pump. I have not ran across one of these & have removed numerous original casting '63 8 bolt pumps & compared them to other early pumps with their original abbreviated cast impellers.



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I picked up the NAPA aluminum housing and cast impeller water pump. A little pricey, but seems like a decent unit and save a little weight.

Guess we'll see how it holds up...

No matter what the cost....... newver ever use cast iompellers that are not curved to match the shield for the water pump..

Read this thread. We been thru it before and figured it all out. ;)

https://forums.maxperformanceinc.com...d.php?t=411256

Read it already...hurt my head, all 71 pages. Divider plate will be clearanced correctly.

Feeling the pain also. Need water pump for my 1964. Got both Napa and Summit 8 bolt after confirming they are supposed to be cast iron impeller. Both were stamped steel. Oreilly had a 4 bolt for a 1964 with cast iron but of course does not fit my 8 bolt. Trying Ames next but more money. I will keep my original 8 bolt pump for possible rebuild as a spare.

I'd be curious to know if anyone has fixed a cooling issue by changing a stamped steel impeller pump for one with a cast impeller.

This is probably what you are looking for.
Go down to post # 10.

https://forums.maxperformanceinc.com...ght=water+pump

On my 61 4 bolt pump it always ran hotter than I thought it should with the stamped steel impeller. Got a four bolt cast impeller and dropped 10-15 degrees in running down the highway temperature. I know the stamped impeller looks like it should pump but it doesn't seem to be up to the challenge. And I don't believe the notion the high water flow won't cool as well as low flow. You need to move both water and air to get the job done and let the thermostat control it..

Cast impellers are always more efficient than the stamped impellers, as long as they have the proper curve to match the divider plate. That's the big reason, or Pontiac wouldn't have used the correct cast impellers right from the factory. ;)

Vertigto, Cardone was the source for the water pumps with cast impeller. Paul Spots and I went up to Philly to show them the ones they were "originally" making were incorrect. Those had shaved cast impellers that didn't conform to the original divider plate. They changed and made the correct curve impellers but neve gave us the part number. They moved to Mexico but came back to Philly. That hasn't work well, from what I was told, as the employees found other jobs and wouldn't come back. So for now I have no idea what's going on up there, and have no contact with the pones Paul and I talked to.

Evans made a really nice one at one time. But not sure if it's still availablem

Doesn't Ames have them?

If you have the original, for $100.00, get it rebuilt. Arthur Gould rebuilds. Takes about 3 weeks.

"Bill"!

Yes Ames has the cast iron impeller pump. And peen over the divider plate to run close to impeller. Flows lots of water and runs no higher than 190. I'll look up Gould for rebuild on old pump.

Pic on the left is a NOS in the GM box 265-301 pump PN 12309445

Pic on right is a later NOS 400-455 pump PN 488377

The pic of the 301 pump isn't the greatest but the vanes look the same. Am missing something? Can you explain abbreviated vane?