65 Big Block Water Pump

[Fred DeNote]

I am wondering if anyone has a source for a correct rebuilt water pump for my 65 BB other that our friends at Goat Hill

Fred

[Joe L.]

Re: 65 Big Block Water Pump

Fred----

These are not really too hard to come by. The 1965 L-78 used the "284" casting and these were used on most all big blocks installed in all Chevrolet models from 1965 through 1968. So, there are a lot of them out there. For a straight-out purchase of a correctly dated pump, try John Pirkle. If a correct date is not too important to you, try your local auto parts store's rebuilt stock.The chances are the the casting you will find is the "284" since that's the most common one. Who knows, considering the allowable 6 month window, the chances are about 1 in 8 that'll you'll find a correctly dated one.

[Bill W.]

Re: 65 Big Block Water Pump

Try Bill Mock or Bob Kunz both can be found in the driveline . Bill

[Joe L.]

Re: 65 Big Block Water Pump

Bill----

I think that Bill Mock is out of the waterpump business. I was told that he sold that business and his inventory to the Pirkles.

[Bill W.]

Re: 65 Big Block Water Pump

Thanks

[Jack H.]

Re: 65 Big Block Water Pump

I've sifted piles of water pumps over the years (moved maybe 4000 of the devils looking for casting number/date/source for various friends) and I'm here to tell you I've come across THREE '284' BB pump cores correct for L78 application! So, the notion that you can go to your local auto parts store and sift through rebuilt cores and have a 1-in-8 shot at coming up with a 'correct' 396 Corvette pump doesn't jive with my reality....

Very few '65 BB's built/delivered and Corvette represents the lion's share (compare to L16 Chevelle, Impala, Etc.). Later, with 427 and 454 as the BB vanguard, volume would climb significantly, but NONE of these '284' pumps are going to be dated or configured right for L78 application (yeah, they'll fit & work).

To the original poster, you should have been on eBay three months ago because I put up one of my two 'backup' pumps. Correct original backing plate, bolts, hub, dated 'B 25 5' and it went begging.... Finally, an L78 fella from Canada bought it for peanuts (about the cost of a rebuild). Made me swear never to put a rare Corvette part out on eBay again!

[Joe L.]

Re: 65 Big Block Water Pump

Jack------

There were 55,454 1965 Impalas manufactured with the L-35 396 engine and 1,838 manufactured with the L-78 engine for a total of 57,292. EVERY SINGLE ONE of these used the GM #3856284 water pump casting. ALL of these vehicles used water pumps which were configured ABSOLUTELY IDENTICALLY to the Corvette L-78 water pump. ABSOLUTELY IDENTICALLY! Of the '284' casting water pumps used for 1965 Chevrolet vehicles, the Corvette L-78 with a total of 2,157 produced, constituted less than 4%. So, there are a lot of 1965 dated '284' castings which are "available" for use on 1965 Corvette L-78s, but which did not originally so-reside on one. These numbers don't even include the SERVICE water pumps manufactured in early to mid 1965 with the '284' casting.

The '284' casting was, BY FAR, the most produced of the short snout, big block water pumps. That's because it was used for ALL Chevrolet big blocks from 1965-1968 across ALL Chevrolet car and truck lines. No other casting was used during these years. By the time that the first successive, short snout water pump casting came along in 1969, GM casting #3940960, the short snout pump was only being used for Corvettes and a few HD truck applications. The next iteration of the short snout water pump, GM casting #3992077, came along in 1971 and the last, GM #386100, was introduced in 1973. All of these latter 3 pumps were used only for Corvettes, some HD trucks, and SERVICE. So, the latter 3 casting numbers are the "rare" big block pump casting numbers; the '284' is, BY FAR, the most common.

The statement that I made regarding 1 in 8 was intended to be a ROUGH, OFF-THE-CUFF estimate; NOT a precisely calculated probability. Also, since I don't think that dates are visible or judged on these pumps, the dating issue is rather non-critical.