Question on 326 Pump - Blueprint

[Kenneth B.]

Re: Question on 326 Pump - Blueprint

Not to bust anybody's bubble but this (from what I can see, bad photo) looks to be a machining drawing not a casting drawing. A casting drawing would have more dimensions describing the casting walls, draft, casting wall thickness and outline.

Back in the day the practice was to have a raw casting drawing and another drawing taking that casting and defining the machining dimensions.

This could also just be an inspection drawing.

I agree that it looks like a inspection drawing. I don't see enough dimensions for it to be a machine drawing. Most of the patterns I built were from casting/machining drawings. Very few had seperate casting drawings. I would love to see the date on a the casting/machining drawing. Just because that drawing is dated 65 dosn't mean that those were also dated in 1965.

[Bob J.]

Re: Question on 326 Pump - Blueprint

This topic was discussed 7 years ago (June 7.2006) in a thread started by Alan Drake under the heading of
C2 WATER PUMP 3859326 OTHER CODE?
You may find it interesting, especially the info provided by a current GM foundry employee by the name Mark Gorney.
Nothing has changed in 7 years !
Bob

[Timothy B.]

Re: Question on 326 Pump - Blueprint

I believe the general consensus is that the #609 is used on the 63's then #609 and #175 on the late 63's and 64's and early 65's until the #326 came into production in late 1964 or the early part of 1965.

The differences are in the casting where the relief clearance is for the pulley as it gets close just behind the 1/2" threaded water outlet.

[John C.]

Re: Question on 326 Pump - Blueprint

Ken and Gene

The drawing can be seen better in Alan Colvin's Chevrolet By the Numbers 1965-69 on page 223. The note at the lower right states- Identical with 3782608 except as shown. The 608 drawing contains your missing dimensions.

John

[Rick A.]

[Michael H.]

Re: Question on 326 Pump - Blueprint

I have the GM print for the 3859326 water pump and I'm the guy that sent it to Rick. It came to me directly from GM. I've had it for years. The print is dated 18 May 1965. It's not fake.

I also have the paperwork from Grey Iron Works, (thanks to one of our members, Mark Gorney) the folks that made the original casting, and the first mention of the 3859326 part is December 1964. That would fit nicely with the May 1965 GM print.

The Grey Iron paperwork shows the 3782609 for 1963, the 3839175 for 1964 and the 3859326 for 65.

No 63 or 64 Corvette ever left the St Louis assembly plant with a 3859326 water pump. As others have mentioned, the 326 myth was started many decades ago and it lives on today.

I'll scan and post the sheets from Grey Iron Works with the dates. If those folks didn't know anything about a 3859326 casting, how in the world can any have been floating around two years before they were even on paper?

Also, the numerical value of a part number itself should tell some folks approximately when a part is released. Part numbers in the 3859xxx range were all released in late 1964 through mid 1965 calendar year. Good examples of this would be most of the new release parts/numbers for the new 396 engine. All are in the same numerical range as the 3859326 water pump. Numbers in that range were not even in the books in 1963.

[Michael H.]

Re: Question on 326 Pump - Blueprint

I just dug out a sheet that was sent to me by Mark Gorney many years ago. Mark worked at Grey Iron Works, the place where water pump castings were made. (and a number of other castings)
This sheet shows the 3782609 casting in the 63 column and the 3839175 in the 64 column. Note the hand written date of June 1963 in the upper right.

These numbers/items are listed about 2/3 of the way down the sheet.

At this time, the 3859326 casting didn't exist on paper, or anywhere else.

[Bob J.]

Re: Question on 326 Pump - Blueprint

Michael , thanks for posting the foundry sheet.
Bob

[John D.]

Re: Question on 326 Pump - Blueprint

Hi Roy, The correct water pump would be the 609. Thanks for asking. John

[Joe L.]

Re: Question on 326 Pump - Blueprint

Hi Roy, The correct water pump would be the 609. Thanks for asking. John

John-----


I think it's possible that some very late 1963 also used the 3839175 and also possible that some very early 1964 used the 3782609. As far as 1963 and 64 go, the pumps would have been completely functionally interchangeable.

[Joe L.]

Re: Question on 326 Pump - Blueprint

John, When did the dating of water pumps start for Corvettes ? The reason I am asking is the 326 pump I have on my SHP engine is not dated, Was the 326 pump used on other GM lines before they went onto corvettes in 65 ? It would seem by that time line corvette pumps would be dated.The drawing is dated 65.
Was it possible to see a 326 not dated in 65. I hope you see what I am trying to explain. Thanks Ed

Edward-----


Unfortunately, the dating of 3859326 waterpumps began November, 1965. So, there's no way that any pumps that might verify a 1963 or 1964 use of such a pump exist. Even if waterpump dating began years prior to 11/65, I don't think any 3859326 waterpumps would be found with 1963 or 1964 dates.

Also, the only other passenger car applications for the external bypass (i.e. '609', '175', '326) small block pumps for 1965 was Chevelles with L-79. However, these castings may have been used for some MD/HD trucks. After 1965 the external bypass small block pump was used through 1967 for Chevy II and Chevelle with L-79 and 1967 Z-28 Camaro. It was also used for 1968 Z-28 Camaro. The latter application was the very last use of an external bypass in a small block passenger car or Corvette. 1972-82 Corvettes did use an external bypass waterpump but the bypass fitting was plugged.

[Roy S.]

Re: Question on 326 Pump - Blueprint

I would personally like to thank each of you for your constructive input in this discussion.

Discussions can occur and reach a conclusion in a positive way without personal attacks; this thread will be evidence of that. I have personally deleted three posts and part of a fourth; those posts in my mind do not contribute anything to a constructive discussion and are the typical half full glass syndrome expressed by so many in open forums. Posts can remain positive and be constructive without being disparaging. I have the capability and the rite as a moderator to do that, those of you that experienced a deleted post or deleted sentence in this string of posts are more than welcome to take it up with me personally via private email not on this technical discussion board.

To my knowledge and I must say up front I could have missed part of this in another thread at an earlier date, this is the first time I have personally seen documentation to support the use of these pumps.
This information has been captured and will be used in the next revision to the 1963/4 Technical Information Manual and Judging Guide.

My conclusion here is very similar to that expressed in 2006, it’s a shame that it has taken until yesterday to actually see the documents that prove this position. The documents may have been presented before but this is the first time I have seen them.

I will not promise the exact verbiage regarding the next revision of the technical manual but it will contain information that indicates it is believed in 1963 the correct pumps are 3782609 with very late 1963 possibly using 3839175 it is believed in 1964 the correct pumps is 3839175 with some very early 1964 possibly using 3782609.

Any member that has an original, unmassaged, unrestored 63 or 64 SHP engine Corvette that can dispute that comment please contact me personally.

With all this said I make the following comments, burden of proof on the judging floor is always with the owner, until someone steps up and does the work for them like has been done here. It’s taken all these years to get this information up front for that I apologize. But here is the truth of the matter with respect to judging. The water pump is 6 points in originality, let’s assume you lost 4 points for the wrong pump, it would still score condition points and your total deduction for this item would be less than .1 percent or 1/10th of a percent 2 out of 4500. I often fight this and only point it out here as proof; sometimes you can’t see the forest for the trees.

While I think it is admirable that there are tree huggers out there trying to protect the trees, in my job as the Judging Chairman I have focused on the forest and will continue too.

[Kenneth B.]

Re: Question on 326 Pump - Blueprint

Very well said Roy. I do think that a lot of us only see the tree with our Corvettes & I have been guilt of that. We are all passionate about our Corvettes. Judging originality is NOT an exact science There are not enough true ORIGINAL Corvettes to go by & things & parts went on Corvettes that were not the norm. NCRS dose a great job of striving to get it right. Our hobby has come this far because of a few dedicated people like you & others here. I don't always agree with everything that NCRS dose but by & large this is the best thing that ever happened for the preservation of the factory original (how it was) Corvette. Keep up the good work Roy! You have to have a thick skin to do your job but I guess you knew that going in.

[Joe L.]

Re: Question on 326 Pump - Blueprint

I would personally like to thank each of you for your constructive input in this discussion.

Discussions can occur and reach a conclusion in a positive way without personal attacks; this thread will be evidence of that. I have personally deleted three posts and part of a fourth; those posts in my mind do not contribute anything to a constructive discussion and are the typical half full glass syndrome expressed by so many in open forums. Posts can remain positive and be constructive without being disparaging. I have the capability and the rite as a moderator to do that, those of you that experienced a deleted post or deleted sentence in this string of posts are more than welcome to take it up with me personally via private email not on this technical discussion board.

To my knowledge and I must say up front I could have missed part of this in another thread at an earlier date, this is the first time I have personally seen documentation to support the use of these pumps.
This information has been captured and will be used in the next revision to the 1963/4 Technical Information Manual and Judging Guide.

My conclusion here is very similar to that expressed in 2006, it’s a shame that it has taken until yesterday to actually see the documents that prove this position. The documents may have been presented before but this is the first time I have seen them.

I will not promise the exact verbiage regarding the next revision of the technical manual but it will contain information that indicates it is believed in 1963 the correct pumps are 3782609 with very late 1963 possibly using 3839175 it is believed in 1964 the correct pumps is 3839175 with some very early 1964 possibly using 3782609.

Any member that has an original, unmassaged, unrestored 63 or 64 SHP engine Corvette that can dispute that comment please contact me personally.

With all this said I make the following comments, burden of proof on the judging floor is always with the owner, until someone steps up and does the work for them like has been done here. It’s taken all these years to get this information up front for that I apologize. But here is the truth of the matter with respect to judging. The water pump is 6 points in originality, let’s assume you lost 4 points for the wrong pump, it would still score condition points and your total deduction for this item would be less than .1 percent or 1/10th of a percent 2 out of 4500. I often fight this and only point it out here as proof; sometimes you can’t see the forest for the trees.

While I think it is admirable that there are tree huggers out there trying to protect the trees, in my job as the Judging Chairman I have focused on the forest and will continue too.

Roy------


One thing that may have "propagated" the notion that the 3859326 pumps were used for 1963 and 1964 is the fact that the 3859326 casting is FAR more common than the 3782609 and the 3837175. The 3782609 casting is quite rare. The only "source" for these is some 1961 and 62-63 Corvettes with 340 and 360 HP engines as well as SERVICE pumps manufactured during this period. They were also used on some MD/HD trucks. The 3837175 is a little more common even though it was primarily only originally used for late 1963 to early 1965 Corvette 340, 360, 350, 365, and 375 HP applications as well as some MD/HD trucks. However, the 3837175 casting was used for many SERVICE waterpumps for quite a few years.

The 3859326 casting is very common (although not with 1/2" NPT fitting) as it was used for most GM SERVICE small block waterpumps for MANY years.

[Timothy B.]

Re: Question on 326 Pump - Blueprint

Rick,

Who are you going to sell your 326 pump to. :-)