I finally dug out my spare pump. It was marked by a vendor on a piece of tape "1935 Chev" It is brand new without the grease cup. It is painted green. There is no GM logo to be found. The pulley has two cast numbers as does the body. With what I found in my 29-40 parts book, they are: Pulley 837872 (32-36 all), 837035 (unknown), Body on the bottom under the pulley end 837609 (1935), 836076 (1936). There is no drain hole but there is a depression in the body at the lowest point where one might have been drilled. I hope this adds to knowledge rather than confusion.

Well, everyone who tried to tell me that the rebuilt pump housing was a 35 was correct. Blind me did not notice that the drain hole had been tapped and a plug inserted. So as Gene had suggested, they put 36 parts in a 35 housing. Finally got in touch with the company and they are going to buy back the 35 housing for $30. If someone else is interested in it, let me know, it's in pretty good condition. If I can just get the pulley on now without breaking something then I'll be set.

Perhaps this is kicking a dead horse but...
I have on my bench two nos GM water pumps. One is 35, one is 36. Both have two casting numbers on the body, one is for a 35, one is for a 36. Neither has a drain hole. One has a cast iron pulley again with casting numbers for both 35 and 36. The 36 pump has a stamped pulley with no numbers. The only difference in the two is that the 36 impeller is about 1/4" thicker and would project that much deeper into the block. Both pumps are painted green. I have been running a 35 pump in a 36 block with some coolant loss and/or overheating. I think the impeller is the answer.

NOS pumps were not painted??????????rebuilts were. A mixture of parts?????????

You have arrived at the answer for the heating problems on a 1936 engine. A '35 water pump will not move enough coolant to properly cool the engine.

Also the 1936 block does not have the baffle behind the pump so the longer rotor is necessary.

The '36 engine coolant capacity was increased significantly over the '35. If memory serves me..and I may be off here...the '36 has 5 quarts more capacity over the '35.
The '36 uses full length water jacket on the cylinders and needs the deeper water pump to move the larger capacity.

Everyone is probably correct but the baffle exists in 36 but is cast in place rather than inserted. I think that the inefficiency is the result of the smaller impeller in a big cavity.

I agree. The larger the gap between impeller and cavity the lower the flow. Water just moves around the impeller instead of being moved in the intended direction.

I just bought on ebay a water pump repair kit, which was listed as being for 1929-34. I'm working on a '29 engine. When the kit arrived, it was actually a 1935 kit. The box is labeled as follows:
QUALITY BUILT
WATER PUMP
REPAIR KIT
Chevrolet, All Models 1935
Price $2.20
No. 4320 837608K

Looking at the contents, they look at first glance to be just like the '29-'32 ones I'm used to. Would this kit work for my '29, or is there some difference that would keep it from working? Actually, if the impeller and bushing are the same, I can dig up the rest of the parts to do the job. So which parts are different? It would save me lots of measuring and checking if someone knows the differences.

Thanks for any help you guys can provide.....

All the Best, Chip

Chip,
According to my Parts catalog, the front bushing is the same but the shaft and impeller assy. are different.
Since the bushing is the same that means the shaft is the same diameter. If the impeller is the same and the shaft is longer, you are in business. Good luck.

Mike

The impeller was made larger in 1935 and enlarged again in 1936.

Thanks guys..... I guess I'll just have to buy a nice '35 car with a bad water pump! Perfect.

All the Best,

Chip

I like the way you think.

Mike