BB water pum identification

[Richard S.]

Water pump removed from my 66 427/390 car is not correct. Can anyone please help to identify. Numbers are and appear as follows:

5821

670-1
Date reads 7 L 7.
Thanks for the help.

[John H.]

Re: BB water pum identification

Looks like a non-GM generic rebuilder casting.

[John H.]

Re: BB water pum identification

Looks like a non-GM generic rebuilder casting.

[Joe L.]

Re: BB water pum identification

Rick and John-----

Yup, that's what it is. However, it's possible that it was a new waterpump that originally came in a Delco box. New Delco waterpumps sold in the last several years, at least, no longer carry the original casting numbers. That's because they are not manufactured internally by GM anymore. They're the same pumps that you can also purchase in the boxes of other brands.

All 1965-68 Corvettes with big block originally used waterpump casting GM #3856284. No exceptions, at all. This casting is decidely not rare, though. It was also used for ALL 1965-68 Chevrolet big block applications. If you purchase a rebuilt waterpump for a Corvette big block application, this is usually the casting you get. This CASTING can be used by rebuilders to build up waterpumps for ANY 1965-74 Corvette big block application. Since there are so many "out there", it's common to find them on a rebuilt waterpump.

By the way, short leg style castings originally used for later 1969 through 1974 Corvette big blocks are not so common. These castings, GM #3940960, GM #3992077, and GM #386100 were used ONLY for Corvette and some MD/HD truck applications. These castings can be built-up into a configuration which will work perfectly in a 65-68 application, though. So, these may be found in a rebuilder's box for a 65-68 application. They were never originally used for those applications, however.

[Joe L.]

Re: BB water pum identification

Rick and John-----

Yup, that's what it is. However, it's possible that it was a new waterpump that originally came in a Delco box. New Delco waterpumps sold in the last several years, at least, no longer carry the original casting numbers. That's because they are not manufactured internally by GM anymore. They're the same pumps that you can also purchase in the boxes of other brands.

All 1965-68 Corvettes with big block originally used waterpump casting GM #3856284. No exceptions, at all. This casting is decidely not rare, though. It was also used for ALL 1965-68 Chevrolet big block applications. If you purchase a rebuilt waterpump for a Corvette big block application, this is usually the casting you get. This CASTING can be used by rebuilders to build up waterpumps for ANY 1965-74 Corvette big block application. Since there are so many "out there", it's common to find them on a rebuilt waterpump.

By the way, short leg style castings originally used for later 1969 through 1974 Corvette big blocks are not so common. These castings, GM #3940960, GM #3992077, and GM #386100 were used ONLY for Corvette and some MD/HD truck applications. These castings can be built-up into a configuration which will work perfectly in a 65-68 application, though. So, these may be found in a rebuilder's box for a 65-68 application. They were never originally used for those applications, however.