Help identify an aluminum waterpump

[Kevin C.]

Hi Everyone,

While recently sorting through some old parts, I came across an aluminum waterpump I remember purchasing from a fellow in the mid-70's. I believe it is for a big block and it has "GM" cast into it along with the part# 3975928. Below the part number the numbers "5421" are stamped into it.Based on the first three digits of the part number (397) I would suspect it is from the 1968/1969 timeframe. I looked in Colvin's "Chevrolet by the Numbers" and "Corvette by the Numbers" and neither book makes any mention of it. Does anyone have any ideas on this part?

Thanks,

Kevin C.

NCRS# 6320

[Joe L.]

Re: Help identify an aluminum waterpump

Kevin-----

The GM casting number 3975928 water pump to which you refer is a SERVICE-only big block water pump. It is still available to this day under GM PART #14058915.

Some Chevrolet parts catlogs show this pump as being applicable to 67-69 Corvettes with HD (i.e. L-88/ZL-1). However, this is a SERVICE application only. These pumps were NEVER used on any PRODUCTION L-88 or ZL-1 engine or, for that matter, were never used on ANY PRODUCTION engine of any sort. ALL L-88s and ZL-1 PRODUCTION engines were built with cast iron water pumps (yes, the "all" aluminum ZL-1 PRODUCTION engines were built with cast iron water pumps).

The GM #14058915 MAY have been used on some SERVICE big block engine assemblies like SERVICE L-88s and ZL-1s sold after 1969 on an over-the-counter basis, but none were ever supplied on PRODUCTION engines actually installed by GM in a PRODUCTION vehicle. The fact that this water pump is not shown in Alan Colvin's books is due to this very reason: his books contain information only on PRODUCTION pieces; not SERVICE-only pieces.