Thanks guys. That helps. Lots of fun projects to try! When I got the car I pulled the radiator hoses off, stuck them in buckets and cranked it to see if the water pump was working. The pump did circulate fluid but I didnt have any good way to check flow rate, etc. I might as well swap out the pump if I am going to go through the effort to take everything apart as a new OEM is about $80 bucks online. I didnt know you could flush the block. I will definitely try that! My guess is the block is full of crud from the old rad.
Be VERY VERY careful about a new water pump. As many in the Pontiac hobby have found out the hard way - you want a pump with the original style cast impeller, NOT the cheep stamped steel impeller.
You will have to go out of your way to get the good one, and ordering on-line is a great way of getting the wrong one. Some have gone to good parts houses like NAPA and had to go through the entire store's supply to find a cast impeller. Or go straight to a good Pontiac repro parts house like Ames who only sells cast impellers.
