3859326 water pump 327

[Wayne M.]

Here's my 1972(?) 326 water pump

Got if from someone with a '64, but obviously not original to anything C2 with that A-24-2 date. This unit was probably rebuilt (dual bolt pattern hub; top bypass fitting drilling larger than 1/2" NPT). I show the "245" pulley and the spacer/reinforcement that it had, due probably to the "wound" from rubbing the casting (arc visible in left of pic).

My Colvin 1965-69 Chev-b-t-Numbers book shows useage to 1968, as you say. But I remember a thread way back (maybe Joe L. ?) that mentioned GM production to mid-70's, maybe for service only.

Hey Jim -- you should see the one on eBay; looks exactly like your pic

[Wayne M.]

Here's my 1972(?) 326 water pump

Got if from someone with a '64, but obviously not original to anything C2 with that A-24-2 date. This unit was probably rebuilt (dual bolt pattern hub; top bypass fitting drilling larger than 1/2" NPT). I show the "245" pulley and the spacer/reinforcement that it had, due probably to the "wound" from rubbing the casting (arc visible in left of pic).

My Colvin 1965-69 Chev-b-t-Numbers book shows useage to 1968, as you say. But I remember a thread way back (maybe Joe L. ?) that mentioned GM production to mid-70's, maybe for service only.

Hey Jim -- you should see the one on eBay; looks exactly like your pic

[Jack H.]

Re: Repro......?

Yes, I have pix, but my policy is NOT to post them until NCRS officially adopts picture posting on this web site. WAY too many threads in the archives today talk to pictures that are no longer resident on the independent site(s) they were originally put up on.

When this issue regarding the poor '326 water pump reproduction came up, others DID post pictures. But, you can also go to Zip Products web site and see a rather fuzzy picture of this 'repro' pump (one that's not sufficiently clear enough to fully reveal the pumps deficiencies).

Basically, the casting number emboss is TOTALLY different in terms of specific font/size, there is NO Saginaw source ID embossed on the back, physical dimenstions of the upper boss that supported the external bypass nipple are different and the LH front surface of the pump (where the casting date insert would have gone into the mold) is HIGHLY irregular...like the mold insert area was quickly filled with a Rube Goldberg fabricated plug.

Last year there were several reports from folks who'd bought 'NOS' and 'correct' '326 water pumps only to find they were from this rather crude reproduction source. But, Zip is only charging something like $125 for the pump and that's not much more than what you'd pay for a rebuild kit + the labor to install the kit. So, you get what you pay for in this case. I suspect the pump WILL fit and function....

[Jack H.]

Re: Repro......?

Yes, I have pix, but my policy is NOT to post them until NCRS officially adopts picture posting on this web site. WAY too many threads in the archives today talk to pictures that are no longer resident on the independent site(s) they were originally put up on.

When this issue regarding the poor '326 water pump reproduction came up, others DID post pictures. But, you can also go to Zip Products web site and see a rather fuzzy picture of this 'repro' pump (one that's not sufficiently clear enough to fully reveal the pumps deficiencies).

Basically, the casting number emboss is TOTALLY different in terms of specific font/size, there is NO Saginaw source ID embossed on the back, physical dimenstions of the upper boss that supported the external bypass nipple are different and the LH front surface of the pump (where the casting date insert would have gone into the mold) is HIGHLY irregular...like the mold insert area was quickly filled with a Rube Goldberg fabricated plug.

Last year there were several reports from folks who'd bought 'NOS' and 'correct' '326 water pumps only to find they were from this rather crude reproduction source. But, Zip is only charging something like $125 for the pump and that's not much more than what you'd pay for a rebuild kit + the labor to install the kit. So, you get what you pay for in this case. I suspect the pump WILL fit and function....

[Jack H.]

Re: Here's my 1972(?) 326 water pump

Understand, the '326 number on the pump is a CASTING number for the raw pump housing. Once, secondary operations (e.g. drill/tap the upper boss for bypass fitting) and add assy components (shaft, bearing, hub, rear plate, gasket) were performed the pump took on a specific GM part number. The part number appears NOWHERE on the finished unit...

The same physical casting with a larger 3/4-inch NPT bypass fitting was used on a LOT of truck engines. Correct originals for the Corvette application with the smaller 5/8-inch NPT bypass were pretty much unique to Corvette and Camaro Z28.

That's why finding a real McCoy water pump drives the price uphill...it's a rather rare birdie. It's also why the NCRS judging text typically advises judges to carefully scrutinize the surface of the upper boss surrounding the external bypass nipple. From the perspective of a mass merchandizer serving the aftermarket with rebuilt pumps, the typical approach was to ship a pump with the BIG 3/4-inch hole and include a blind plug as well as a 3/4-inch to 5/8-inch reducing sleeve. You got a one fits all solution!

BUT, if one is SERIOUS about making the truck version of the pump become a Corvette '326 pump, you CAN install a cast iron reducing sleeve, machine it back to being flush with the upper boss of the pump's housing and manually re-texture the boss surface to appear to have an 'as cast' continuous appearance.

When this is done properly and the 'restoration' pump is installed + painted, it's simply IMPOSSIBLE to detect on the judging field. I suspect this technique is what's used by several of the current sources for 'correct/original' 326 water pumps....

[Jack H.]

Re: Here's my 1972(?) 326 water pump

Understand, the '326 number on the pump is a CASTING number for the raw pump housing. Once, secondary operations (e.g. drill/tap the upper boss for bypass fitting) and add assy components (shaft, bearing, hub, rear plate, gasket) were performed the pump took on a specific GM part number. The part number appears NOWHERE on the finished unit...

The same physical casting with a larger 3/4-inch NPT bypass fitting was used on a LOT of truck engines. Correct originals for the Corvette application with the smaller 5/8-inch NPT bypass were pretty much unique to Corvette and Camaro Z28.

That's why finding a real McCoy water pump drives the price uphill...it's a rather rare birdie. It's also why the NCRS judging text typically advises judges to carefully scrutinize the surface of the upper boss surrounding the external bypass nipple. From the perspective of a mass merchandizer serving the aftermarket with rebuilt pumps, the typical approach was to ship a pump with the BIG 3/4-inch hole and include a blind plug as well as a 3/4-inch to 5/8-inch reducing sleeve. You got a one fits all solution!

BUT, if one is SERIOUS about making the truck version of the pump become a Corvette '326 pump, you CAN install a cast iron reducing sleeve, machine it back to being flush with the upper boss of the pump's housing and manually re-texture the boss surface to appear to have an 'as cast' continuous appearance.

When this is done properly and the 'restoration' pump is installed + painted, it's simply IMPOSSIBLE to detect on the judging field. I suspect this technique is what's used by several of the current sources for 'correct/original' 326 water pumps....

[Joe L.]

Re: Here's my 1972(?) 326 water pump

Wayne------

Yes, the 3859326 casting was being manufactured well into the late 70's. In fact, I think it may have continued into the early 80's. It was the casting used for all SERVICE 1955-68 small blocks (plus, 69-70 Corvette small blocks) for many years. I think that occurred since it was the last short leg, external bypass type pump casting released. The external bypass type pump could be used to SERVICE all small block applications requiring the short leg pump.

[Joe L.]

Re: Here's my 1972(?) 326 water pump

Wayne------

Yes, the 3859326 casting was being manufactured well into the late 70's. In fact, I think it may have continued into the early 80's. It was the casting used for all SERVICE 1955-68 small blocks (plus, 69-70 Corvette small blocks) for many years. I think that occurred since it was the last short leg, external bypass type pump casting released. The external bypass type pump could be used to SERVICE all small block applications requiring the short leg pump.