I have a 1996 24...it has a 502 magnum with closed cooling. The motor used to run at 165 degrees..lately going up to 180 degrees. I changed the thermostat and the raw water pump and had no change in temp. Does anybody know the normal operating temperature for this engine???

180°F is still OK imo.
I would bet there is some build up on the sending unit giving you the different reading.
If it's not the sending unit, then maybe the heat exchanger is plugged up some.

Flush the heat exchanger... 99% of the time its a plug in there somewhere. As Pat said 180 is still in the green but a 15 degree jump is a little unusual.

Agreed. If you recently lost an impellor and didn't get all the pieces out, they will go downstream to this point and reduce flow. Anytime you change waterpump count the vanes on the impellor and make sure they are all counted for.

Thanks for your help guys. i will clean the tubes in the heat exchanger and then check the sending unit.ill let you know how i made out