3859326 water pump 327

[Jim V.]

I have seen 3859316 pumps with both small and large casting numbers. Was there a definite transition from the smaller to the larger at some point? I surmise the GM3 casting mark notates some chronology as well with increasing numerals. Here is an example of the smaller casting number on a no-date (pre Nov 66) pump.

Thanks!

[Jack H.]

Re: 3859326 water pump 327

Flip your pump over and look at the rear side of the casting. I'll bet, on the pump you posted the picture of, there's a rather large 'S' embossed which identifies the foundry source as Saginaw. Similar '326 castings were also made at Tonawanda which could well be one of the sources for the differences in emboss font size you've observed on different pumps. The size of the emboss font + exact placement of the insert in the mold IS one of the known areas of difference between Saginaw/Flint blocks and those from Tonawanda....

[Jack H.]

Re: 3859326 water pump 327

Flip your pump over and look at the rear side of the casting. I'll bet, on the pump you posted the picture of, there's a rather large 'S' embossed which identifies the foundry source as Saginaw. Similar '326 castings were also made at Tonawanda which could well be one of the sources for the differences in emboss font size you've observed on different pumps. The size of the emboss font + exact placement of the insert in the mold IS one of the known areas of difference between Saginaw/Flint blocks and those from Tonawanda....

[Jim V.]

Re: 3859326 water pump 327

Jack...sure is a Saginaw casting. Shows an S3 on the back. Now...did both foundries continue to supply castings through the life of the "326" pump (65 - 68)?

Thanks

[Jim V.]

Re: 3859326 water pump 327

Jack...sure is a Saginaw casting. Shows an S3 on the back. Now...did both foundries continue to supply castings through the life of the "326" pump (65 - 68)?

Thanks

[Jack H.]

Re: 3859326 water pump 327

To my knowledge both foundries made these pumps as long as engines being built called for them. Plus, St. Catherine's in Canada might have produced the same casting....

Once, they were no longer called for on production engines, the remaining buyer would have been GM service. The reduction in overall volume might have closed or moved production as made economic sense.

[Jack H.]

Re: 3859326 water pump 327

To my knowledge both foundries made these pumps as long as engines being built called for them. Plus, St. Catherine's in Canada might have produced the same casting....

Once, they were no longer called for on production engines, the remaining buyer would have been GM service. The reduction in overall volume might have closed or moved production as made economic sense.

[Wayne M.]

Think they made these into the '70's

I have one A_24_2; large S6 on the back, and large GM6 on the front, with small 3859326 directly under.

[Wayne M.]

Think they made these into the '70's

I have one A_24_2; large S6 on the back, and large GM6 on the front, with small 3859326 directly under.

[Jack H.]

Add-on

There are also some current 'reproductions' of this pump on the market that are VERY POOR in terms of their correspondence to the real McCoy, factory original, pumps from GM. This was the subject of a prior thread (in the archives) and one of the distinguishing features of the 'repro' is its emboss for the casting number doesn't look ANYTHING like the original in terms of font size/style.

Could it be that this is mixed into this thread over and above the typical modest distinctions between GM foundries/factories for original parts???

[Jack H.]

Add-on

There are also some current 'reproductions' of this pump on the market that are VERY POOR in terms of their correspondence to the real McCoy, factory original, pumps from GM. This was the subject of a prior thread (in the archives) and one of the distinguishing features of the 'repro' is its emboss for the casting number doesn't look ANYTHING like the original in terms of font size/style.

Could it be that this is mixed into this thread over and above the typical modest distinctions between GM foundries/factories for original parts???

[Jim V.]

Repro......?

Was not aware of any repro.... Might you have a pic to share?

[Jim V.]

Repro......?

Was not aware of any repro.... Might you have a pic to share?

[Jim V.]

1972?

Wayne...you thinking that is a 1972 service replacement that you have? Can you post a pic? I know the pump had application for 65 - 68 per Colvin's book.

Thanks

[Jim V.]

1972?

Wayne...you thinking that is a 1972 service replacement that you have? Can you post a pic? I know the pump had application for 65 - 68 per Colvin's book.

Thanks