C2 water pump 3859326 other code?

[Alan Drake]

have located a 3859326 water pump core for my March 64 FI car - think that's the correct one.
Noticed on the front on theother side of the shaft another number on a small raised boss - 176
Is this a date code?? Did not think these 326 pumps had a date code!
Please advise
Thanks Alan

[Michael H.]

Re: C2 water pump 3859326 other code?

Alan,

As per several in depth discussions on this subject, I think most everyone agrees that the 3859326 pump never made it to production for the 64 model year. It's thought that it may have been first seen in mid 65 production.

The commonly accepted casting number for the 64 pump would be 3839175. It's also possible that the 3782609 may have carried over from 63 to 64.

I'm not sure what the "176" is on your 326 pump.

[Alan Drake]

Thanks I'll find a 3839175 *NM*

[Mark G.]

[Mark G.]

[Wayne M.]

A caveat on "175"s

If I recall correctly from earlier threads (Joe Lucia) confirmed that the 175 was produced over 2 decades, so a C_13_5 date could well be 1975.

[Alan Drake]

WP 3782609 or 3839175 which one is best

Will need to find a water pump for my Mar 64 FI car. It appears that either the 609 or the latter 175 would be acceptable, however since I do not have anything now which is the better one to look for?
Past post have lead me to believe that the 609 is possible for a 64, but not likely. I also believe the 609 has no date code making it a simplier upgrade.

Was going to select the 175 since it appears that it was a 64 unit that everyone agrees about. Now if the 175 has a date code it just makes it a harder find.

Thanks for all the info, I think
signed confused

[John D.]

Re: WP 3782609 or 3839175 which one is best

Alan, I recently got a 609 pump for my '63 to replace the 326. But at our shows I find that the judges say you can't easily see the number and so if it's the correct configuration, has the correct bypass fitting with the proper logo in the correct size hole (no adapter) they give the owner a slash and move on. Meanwhile we know that we must have the correct part whether it is seen or judged. It's like paying mega bucks for an oil pan plug with a logo when a magnetic plug is the way to go. Can't see the logo anyhow with the car on the ground.

[Jim L.]

Re: WP 3782609 or 3839175 which one is best

ho! but there is a difference between the 609 & 326 that is visable. the casting on the 326 is a larger dia. at the by-pass hose boss to permit a 3/4" fitting, where as the 609 is smaller and not large enough to make it into a 3/4" fitting at all. the 609 also has a rounded boss where the water pump pully just clears. the 326 has a flat edge in the same area, not rounded. i have both pumps in hand if a picture is needed to better describe the difference. it is very easy to tell them apart!!
jim

[Tracy C.]

no date code on my "175" Late 63 340 hp *NM*

[John D.]

Re: WP 3782609 or 3839175 which one is best

Jim, You info on the difference between the two pumps is something for else to learn. I will have my 326 pump back in a couple of days and will compare it the the 609. But I am sure the gang would like to see the differences. Then a sketch could be put in the judging manual. Thanks for your keen eyes.

[Joe L.]

Re: WP 3782609 or 3839175 which one is best

Jim-----

Your description of the differences between the '609' and the '326' is exactly correct. The "flat edge" that you describe on the '326' is actually a pulley relief that is cast into the bypass fitting boss. All '609' pumps were originally machined for a 1/2" bypass fitting. The '326' castings were machined for both 1/2" and 3/4" bypass fittings.

[Joe L.]

Re: no date code on my "175" Late 63 340 hp

Tracy-----

The '175' waterpump castings that were used in PRODUCTION were not dated, as were the SERVICE castings available during the early 60's.

However, the '175' casting was used for many SERVICE waterpumps that were manufactured much later. These were used for all 55-68 small block SERVICE requirements and included a plug for non-external bypass engines. Later, the '326' casting became the predominant casting for small block short leg SERVICE waterpumps.

So, any '175' casting that is found with dates is a SERVICE casting. If one finds one with a year date of "4", that refers to 1974, not 1964.

If one cleverly and carefully grinds off the date on a later SERVICE '175' casting, then one has an "undated casting" as is correct for 1963-E65.

[Tracy C.]

Thank you Joe. I appreciate your followup ! *NM*

[Joe L.]

Re: Thank you Joe. I appreciate your followup !

tracy-----

One thing that I may not have been clear on is that the '175' castings produced in the early 60's did not have dates and this applied to BOTH PRODUCTION and SERVICE units manufactured during that period. Later, the '175' casting was "resurrected" and used for SERVICE for all 55-68 Chevrolet small block applications (plus, 69-70 Corvette small block applications). After its "resurrection" the '175' casting "sprouted dates". All of these dated castings were the later SERVICE-only units.

'175' castings found with year dates of "2", "3", "4", and "5" might confuse restorers. On the one hand, they are told that original '175' castings used on early 327's with external bypass have no dates. On the other hand, they find a casting which appears to be "correctly dated" for their car (or, others) and it has dates. So, what's with this? Well, the "2", "3", "4", or "5" year codes refer to 1972, 1973, 1974, or 1975. Not a problem with Tonawanda castings, of course, which may have a 2 digit year code. However, I don't think that any of the '175' SERVICE castings were ever cast at the Tonawanda foundry.