70 Corvette W/P pulley 3890419 or 3995643?

[David L.]

I have many vintage Chevrolet parts catalogs (over 55 different ones from 1957 to 1981) but I can not find which water pump pulley is correct for the 1970 Corvette (350)(exc. C.A.C., H/Per., Sp H/per.). I have a 1969 Chevrolet Parts Catalog (Oct. 1968), a 1969 Corvette Parts Catalog (Sept. 69), and a 1972 Corvette Parts Catalog (Sept. 1971). The 3995643 pulley is not listed in either of my 1969 catalogs but it is listed in my 1972 catalog. The 1972 catalog lists the 3890419 pulley for 69-70 Corvette(350)(exc. C.A.C., H/per., Sp. H/Per.) and also lists the 3995643 pulley for 70 Corvette (350)(exc. H/Per., Sp. H/Per., C.A.C.).

I have a 1969 Corvette AIM but not a 1970 Corvette AIM.
Did early 1970 Corvettes use W/P pulley 3890419 and late 1970 Corvettes use W/P pulley 3995643? Both pulleys appear to be identical and the dimensions are the same (about 6 5/16" O.D. and about 2 13/16" in depth). Both pulleys have the code "CT" stamped after the stamped part number.

According to Chevrolet Parts History GM 3890419 was replaced with GM 3995643 in December 1971.

In the first photo the 3890419 pulley is on the left.

Dave

[Joe L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

I have many vintage Chevrolet parts catalogs (over 55 different ones from 1957 to 1981) but I can not find which water pump pulley is correct for the 1970 Corvette (350)(exc. C.A.C., H/Per., Sp H/per.). I have a 1969 Chevrolet Parts Catalog (Oct. 1968), a 1969 Corvette Parts Catalog (Sept. 69), and a 1972 Corvette Parts Catalog (Sept. 1971). The 3995643 pulley is not listed in either of my 1969 catalogs but it is listed in my 1972 catalog. The 1972 catalog lists the 3890419 pulley for 69-70 Corvette(350)(exc. C.A.C., H/per., Sp. H/Per.) and also lists the 3995643 pulley for 70 Corvette (350)(exc. H/Per., Sp. H/Per., C.A.C.).

I have a 1969 Corvette AIM but not a 1970 Corvette AIM.
Did early 1970 Corvettes use W/P pulley 3890419 and late 1970 Corvettes use W/P pulley 3995643? Both pulleys appear to be identical and the dimensions are the same (about 6 5/16" O.D. and about 2 13/16" in depth). Both pulleys have the code "CT" stamped after the stamped part number.

According to Chevrolet Parts History GM 3890419 was replaced with GM 3995643 in December 1971.

In the first photo the 3890419 pulley is on the left.

Dave

Dave------


I don't think that any 1970 Corvettes ever used the GM #3995643 pulley. For one thing, I don't think this pulley even existed during the 1970 model year. For Corvettes, the 3995643 is a SERVICE-only pulley

[David L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Joe,

I tend to think the same as you. However, I have a 1971 Chevrolet Dealer Parts and Accessories Price Schedule (effective March 1, 1971) and both 3890419 and 3995643 are listed.

GM # 3890419 is listed at $4.00 (list price) for use on Chevrolet, Buick, and Oldsmobile models.

GM # 3995643 is listed at $3.95 (list price) for use on Chevrolet and Buick models.

According to Chevrolet Parts History 3890419 was replaced with 3995643 in December 1971.

I have both pulleys and they both appear to be identical (except for the stamped part number) with the exact same dimensions and they both appear to been have made using the same construction methods. Each pulley weighs 1 lb. 12 oz.

I believe that a 1970 Corvette Assembly Manual could shed some light. I have all the Corvette assembly manuals from 1962 to 1969 but not one for 1970.

Dave

[Joe L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Joe,

I tend to think the same as you. However, I have a 1971 Chevrolet Dealer Parts and Accessories Price Schedule (effective March 1, 1971) and both 3890419 and 3995643 are listed.

GM # 3890419 is listed at $4.00 (list price) for use on Chevrolet, Buick, and Oldsmobile models.

GM # 3995643 is listed at $3.95 (list price) for use on Chevrolet and Buick models.

According to Chevrolet Parts History 3890419 was replaced with 3995643 in December 1971.

I have both pulleys and they both appear to be identical (except for the stamped part number) with the exact same dimensions and they both appear to been have made using the same construction methods. Each pulley weighs 1 lb. 12 oz.

I believe that a 1970 Corvette Assembly Manual could shed some light. I have all the Corvette assembly manuals from 1962 to 1969 but not one for 1970.

Dave

Dave-----


The only pulley shown in the 1970 AIM is the 3890419.

[David L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Dave-----


The only pulley shown in the 1970 AIM is the 3890419.

Joe,

Thanks for the information. I guess this case is closed.

Dave

[Joe L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Joe,

Thanks for the information. I guess this case is closed.

Dave

Dave------


Not necessarily. We have no way of knowing if the copies of the AIM that served as the "masters" for the commercially available "re-prints" we all use today included all revision pages. So, there could have been revisions that are not included in the copies we use. This applies to any year AIM.

However, in this case, I think the AIM page including the waterpump pulley is the correct and final page. Why? Well, for one thing, the 1971 AIM shows the 3890419 pulley as being used for small blocks. However, I believe that is an error. I do not believe that any 1971 Corvette small blocks ever used the 3890419 waterpump pulley. If they did, they would also have had to use the 1955-70 style waterpump and I don't think that any ever did.

I believe that all 1971 Corvettes with small block and without C-60 used waterpump pulley GM #3991423. This pulley was released for the 1971 model year and is applicable only to Corvettes and some MD/HD trucks.

Note that pulley GM #3995643 has a part number which is sequentially higher in number than the 3991423. This implies that it was released after the 3991423 or, by further implication, sometime after the start of the 1971 model year. Curiously, the 3890419 was replaced by the 3995643 in December, 1971 which would be about 3 months after the start of the 1971 model year. That's when I believe the 3995643 was actually released. I do not think it was ever a pulley that was used in PRODUCTION for any Corvette.

[David L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Curiously, the 3890419 was replaced by the 3995643 in December, 1971 which would be about 3 months after the start of the 1971 model year. That's when I believe the 3995643 was actually released. I do not think it was ever a pulley that was used in PRODUCTION for any Corvette.

Joe,

I think you mean the 1972 model year as 3 months after December 1971 would be during the 1972 model year.

I just can not understand why there was a part number change because the two pulleys appear to be identical (size, weight, and construction method). A parts person at Dobles Chevrolet in Manchester, NH, told me many years ago that GM changed part numbers in the early 1970's during the "price freeze" so that they could sell the same part at a higher price because technically it was a different part. This is not the case here as in March 1971 the 3890419 pulley was $4.00 and the 3995643 was $3.95.

Thanks again for your comments.

BTW, have you ever been to Regina's Pizzeria in the North End?

Dave

[Ray K.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

After looking at my P & A catalogs, it seems to me that the #3890419 pulley would be correct for the '70 model as described.

When new part numbers appeared in the catalog such as the 3995643 they often replaced the number that existed previously if the design had not changed.

Joe's part number analogy and sequential higher number also seems correct to me.

I think the " price freeze " in the early '70's had more to do with union labor contracts that in turn revised the pricing structure.

Ray

[Joe L.]

Re: 70 Corvette W/P pulley 3890419 or 3995643?

Joe,

I think you mean the 1972 model year as 3 months after December 1971 would be during the 1972 model year.

I just can not understand why there was a part number change because the two pulleys appear to be identical (size, weight, and construction method). A parts person at Dobles Chevrolet in Manchester, NH, told me many years ago that GM changed part numbers in the early 1970's during the "price freeze" so that they could sell the same part at a higher price because technically it was a different part. This is not the case here as in March 1971 the 3890419 pulley was $4.00 and the 3995643 was $3.95.

Thanks again for your comments.

BTW, have you ever been to Regina's Pizzeria in the North End?

Dave

Dave-----


Yes, I was thinking December, 1970 instead of December, 1971. It was pretty late when I composed that e-mail and my brain was not working right.

The 3995643 was available in SERVICE well prior to the date of discontinuation of the 3890419. From what I can tell, it was first available in January, 1971 or, perhaps a month or two prior to that time. That's just about when I would expect given the part number sequence.

The 3995643 then became supercessive to the 3890419 in December, 1971 which is likely when the inventory of the 3890419 ran out.

Yes, I have been to Regina's Pizza in Boston's North End. I was last there about 2 years ago with my cousin Johnny and a group of MIT professors and instructors. My cousin Johnny was born and raised in Somerville (but now resides in Thailand). My grandfather was born in the North End just a short time after my great grandparents emigrated from Italy and in a house just a few blocks from Regina's Pizza.