Water pump numbers

[Jack P.]

I found in an old box of mine a water pump that I had removed some years ago. I have owned my 66 327/350 since 1970, lots of pumps replaced.

This pump is GM 5 # 3859326 with a build date of C 20 8

Would this have been the replacement part from GM sold to me in 70 or 71

I know they did not date them prior to 66

Jack

[John H.]

Re: Water pump numbers

This pump is GM 5 # 3859326 with a build date of C 20 8

Would this have been the replacement part from GM sold to me in 70 or 71

Jack -

Most likely, with a casting date in 1968.

[Jack P.]

Re: Water pump numbers

Jack -

Most likely, with a casting date in 1968.

Is it worth rebuilding for a spare, or can it be traded as a core for a date correct one for my 66 ? ( Did I really ask that question ? )

Jack

[Joe L.]

Re: Water pump numbers

Is it worth rebuilding for a spare, or can it be traded as a core for a date correct one for my 66 ? ( Did I really ask that question ? )

Jack

Jack------

The 68 manufactured pump will likely have a 3/4" NPT bypass tapping on the top. Your original will use 1/2" NPT size. You can convert the 3/4" to 1/2" with a bushing and, if you do it cleverly, it will be undetectable.

The '326' was used VERY commonly for later SERVICE waterpumps, though. So, the one you have is by no means a rare piece.