1964 365hp correct #

[Michael H.]

Re: 1964 365hp correct #

Jack -

The photo robot looks for both filename AND file size; I run into this frequently, and just rename and resize the image so I can post it again (or I upload it to my photo site and "call" it in full size). John Waggoner posted another workaround, but I can't find it.

Or, you can just delete it from your previously posted photos. Then you can repost it. It's somewhere in control panel/attachments.

[William M.]

Re: 1964 365hp correct #

Lynn, Jack, Joe and Mike,
Jack: please read my post again. I said that over the years I have only had two "real" undated "175" water pumps with the 1/2" NPT bypass fitting hole on top(in my picture). I also stated that I have had many(perhaps 100+) of dated "175" water pumps with the 3/4" NPT bypass fitting hole on top. These all had the flat area on the front edge of the bypass fitting boss like a "326" water pump.
Joe: the picture(Polaroid picture I took in the early 1990's) that I posted was of a "real" undated "175" water pump with the 1/2" NPT bypass fitting hole on top. Note that the bypass boss is rounded like a "609" bypass boss with no flat area on the front like a "326". Since the hub height spec is 5&11/16" it clears the water pump pulley.
NCRS probably does not recognize the 3839175 water pump because of its very limited usage. Most people have not heard of it.
Regards,
Bill Mock #93

[Michael H.]

Re: 1964 365hp correct #

NCRS probably does not recognize the 3839175 water pump because of its very limited usage. Most people have not heard of it.
Regards,
Bill Mock #93

Agree, the 3839175 was only used for late 63 and much of 64, but only on Corvette and HD truck. Compared to the large number of trucks that used the 175 with 3/4" outlet during that time, we can see why the number of used Corvette pumps with 1/2" outlet is so limited.

Good to see you here Bill. Been a long time.

Michael

By the way, did your printer ever learn how to spell enthusiasts?

[Joe L.]

Re: 1964 365hp correct #

Lynn, Jack, Joe and Mike,
Jack: please read my post again. I said that over the years I have only had two "real" undated "175" water pumps with the 1/2" NPT bypass fitting hole on top(in my picture). I also stated that I have had many(perhaps 100+) of dated "175" water pumps with the 3/4" NPT bypass fitting hole on top. These all had the flat area on the front edge of the bypass fitting boss like a "326" water pump.
Joe: the picture(Polaroid picture I took in the early 1990's) that I posted was of a "real" undated "175" water pump with the 1/2" NPT bypass fitting hole on top. Note that the bypass boss is rounded like a "609" bypass boss with no flat area on the front like a "326". Since the hub height spec is 5&11/16" it clears the water pump pulley.
NCRS probably does not recognize the 3839175 water pump because of its very limited usage. Most people have not heard of it.
Regards,
Bill Mock #93

Bill-----


For many years I have wondered why GM created both the 3839175 and the 3859326 since, other than the casting number, I can see no difference between them. I think we might have now figured it out.

Apparently, the original version of the 3839175, as evidenced by your photo of an original 64-era 3839175, did not have the pulley relief on the upper bypass boss.

If you will note the 3839175 pump in the old photo that Jack posted some time ago, it appears to me that the relief is GROUND as part of a machining operation and not a feature of the casting.

It may be that when GM discovered that a relief on the 175's oversize bypass boss (compared to the '609') was necessary for some pullies, they decided that it would be more cost-efficient to create a new casting that included the relief as a feature of the casting and eliminate the need for a machining operation. Thus may have been born the 3859326.

Of course, the "fly-in-the-ointment" is the later SERVICE versions of the 3839175 castings which appear to have a cast-in relief. I'm not sure what happened here, but it might be that some 3839175 patterns were modified to provide for a cast-in relief and the casting number was not changed. For limited SERVICE-only use, it might not have been worth the trouble to change the casting number.

[Timothy B.]

Re: 1964 365hp correct #

Bill,

That's a great picture of a original 3839175 pump, at least I know that this pump existed with a 1/2" bypass.

It's interesting that the mold # is GM#4 and Jack's picture of a 609 is GM#4. I guess we will never know if molds were modified to save $$, this may account for the later 175 mold with the 326 features.

[William M.]

Re: 1964 365hp correct #

Mike,
Re: My original businees card
You have a true collectors item! When I first did my business card many years ago, the print shop that I used printed my business card without having me proof it. When I got them back from the printer, I noticed that they had spelled "Corvette Enthusiasts" as "Corvette Enthusiastes". I called them on it and they corrected their mistake and reprinted them for me at no charge. I was needing them for Bloomington at the time and they did not have the reprints ready in time so I used the typo cards.
Bill Mock #93

[William M.]

Re: 1964 365hp correct #

Lynn, Jack, Joe, Mike and Bob,
Re: 3839175 Water Pump - 1964 Corvette #15153 with 375hp327 engine
Please find a picture of the original 3839175 water pump on 1964 Corvette #15153 and copies of other documents of interest. Joe - note that it clears the water pump pulley.
Also, 1964 Corvette #03429 with 375hp327 engine owned by Gene Tucker has a 3839175 water pump.
Regards,
Bill Mock #93

[Michael H.]

Re: 1964 365hp correct #

So, from posts/information from a previous discussion here a few years ago, and more info that has been posted again recently, is there anyone that does NOT agree that the 3782609 was used for most of the 63 model year, the 3839175 randomly from late 63 to late 64 model year, and the 3859326 from late 64 and 65? (and later)

[William M.]

Re: 1964 365hp correct #

Lynn, Jack, Joe and Mike,
Re: I found better pictures of the 3839175 water pump that I had previously posted a picture of. This water pump was RARELY used on late 1963 Corvettes and 1964 Corvettes with the solid lifter engine. This would explain why hardly anyone has ever seen this pump except for later "175" water pumps with the 3/4" NPT bypass fitting hole, casting date and flat area on the front of the bypass fitting boss. Usage appears so slim that one can't say it was the norm for late 1963's and 1964's otherwise we would have seen many of them over the years and NCRS would have recognized it years ago.
Regards,
Bill Mock #93

[Michael H.]

Re: 1964 365hp correct #

3839175 This water pump was RARELY used on late 1963 Corvettes and 1964 Corvettes. Bill Mock #93

I agree. I definitely haven't seen many 175 pumps on Corvettes in the last few decades.

[Martin T.]

Re: 1964 365hp correct #

Michael, I believe you have summed all this up well. Under that pretext, I will go along with Bill Mock's suggestion. One 326 pump to be installed. I believe a GM-1 non-dated version to be correct per this discussion.

Bill, were you able to reach Lou?

[William M.]

Re: 1964 365hp correct #

Martin,
The original "real" undated 3859326 water pumps with the 1/2" NPT bypass fitting hole(not sleeved) had GM1, GM2, GM3 or GM4 and a S1, S2, S3 or S4 on the back side. Any of them would be correct for your application.
Bill Mock #93

[John R.]

Re: 1964 365hp correct #

Was reading this post and found that I have a NOS or NORS ....175 pump with GM 16, date looks like I208 or I209 (per the date casting, the 8 or 9 could be a 3 but I doubt it..). Has the relief cast into the boss.


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[Joe L.]

Re: 1964 365hp correct #

Was reading this post and found that I have a NOS or NORS ....175 pump with GM 16, date looks like I208 or I209 (per the date casting, the 8 or 9 could be a 3 but I doubt it..). Has the relief cast into the boss.

John------


These '175' castings were used for quite some time for SERVICE waterpumps, well after they ceased to be used for PRODUCTION. However, I would not completely rule out the possibility that some were even used for PRODUCTION right up to the time that external bypass pumps were last used for passenger car. including Corvette engines in 1967.

[Paul Y.]

Re: 1964 365hp correct #

Jack, I would be happy to show you my 175 pump with the small overflow.

No, I do not take you to 'argumentative'...

I was simply stating the reality of our judging system. There are many places where 'loop holes' exist, different things are treated differently based on specfic division and NTL. But, that's the way things are.

As far as the others who want to see 'PROOF' from the NTL, you should take that up with the specific NTL. But, in some cases, I suspect you'll be pushing on a rope!

So, don't shoot the messanger on this one. You'll note that JG information DOES change over time as our standards are dynamic.

On this '609/'175/'326 pump issue, you all know what the current thinking is regardless of right/wrong. So, it's your car, go select the part you believe to be correct/original and then be prepared to take deduction(s) depending on which judges you happen to pull.

The alternative is to blindly follow the text of the current JG book and then YEARS later, if/when the text is changed, you're stuck with a water pump that turns out to be WRONG...

The act of restoration is like duck hunting. You have to lead the airborne flock with your gun to bring the birdies down... It's NOT a completely solved science and there IS an artform content to the sport/hobby.

Yes, there is an obvious visual difference between a '609 and '175/326 pump housing (forget about date coding or casting source). But, the distinction between a '175 and '326 pump is gossamer at best!

One last comment, while I've seen that rare/elusive '326 pump with 1/2" NPT fitting on the upper boss (Corvette/Camaro applications) versus the larger 3/4" NPT bores associated with truck applications, I've yet to see a '175 housing with the small bore...

What's that mean/say? Probably not much.

The '175 casting is indeed a rare item and I've only seen/had maybe 20 of them over the years. So, this could be a simple case of small sample statistical skew. Or, if could indeed be a form of 'proof' that these, for whatever reasons, simply weren't used in Corvette applications...