My 77’ Chevy c-10 blew its water pump, now I am having a lot of trouble finding the right pump. My truck does not have the original motor. It is an inline six and I have found that most of the time, parts for the 79’ 250ci. inline six fit the motor. Unfortunately, the water pump for the 79’ 250ci is the right height, but has a different impeller that does not fit in the block, but the 73’ 250ci.‘s water pump does fit, it’s just too short for the pulley to fit on top. Also, the computers at auto zone said that the 79’ 250ci. has a 2bbl carb whereas mine only has a 1bbl carb. Could I have the 292ci. inline six? Its Sunday, so all the dealers are closed today and I need this truck fixed today, it my daily driver. Is there any way to tell exactly what motor is in my truck? Any websites to look up motor serial numbers?
You really need the engine casting number, the carb is of little relevance since it could have been changed.
See if you can find the block casting number and I’ll see if I can find a Chevy ID resource. There are a few around.
Thanks. This is number you need i think. On the passenger side of the block it says;
377127
GM
79
That makes me think its a 79’.
Here ya go : http://www.inliners.org/casting/numbers.html
The list says your engine is a 250, you should be able to get a pump for Autozone easy enough. Good luck.
I already tried autozone, and i could not find the right pump. They are all a little different. To top it off, the parts store that sold me the first pump threw away my old one.
Then you’re only recourse is to measure the block impellor aperture diameter and depth, go along to Autozone / Napa and hope they have the time to wade through their stock until they find the correct one.
I’m assuming you have a gasket that matches the casting pattern, take this along to ensure your castings match.
Yeah, all the pumps are almost identical, just different heights and impellers
When you say the parts store junked your old pump, did you ask if their garbage had been collected ?
They might just be reluctant to wade through their garbage, you might be a little more inclined under the circumstances 
Click on this link to Auto Zone http://www.autozone.com/R,APP197541/vehicleId,1321401/initialAction,partProductDetail/store,1140/partType,00095/shopping/partProductDetail.htm It lists a water pump for a 4.1L (which is 250 cubic inches), 1bbl. If you have the old w/p gasket, or can trace the mounting surface of the old w/p, you can match that to the w/p the store has.
I’ve had a lot of good experinces with LMC truck parts. You can look them up on line, but like you say it is Sunday. Just a future reference word of advice. Shame on you for going to Autozone. One reason being that they are trying to sell you a self-judged universal part for a unique engine. If Napa is open on Sundays in your nitch-in-the-woods use them. They have an amazing reference system to find the right part. Especially if you take the old part in, they can back track the part number.