Reply to "condensate in oil"

Will says 180, I've read in the past that the Cleveland and Windsor were designed to run at 192. I don't have any sources to tell you why, but it's something I've read over the years. I'm running a Robert Shaw 192 in my 351C, which doesn't help you with your Windsor, but any decent auto shop should be able to sell you a thermostat in either 180 or 192 flavors, if you tell them you have a Windsor.

As far as your temp goes, if you have boiling in your tanks but your temp gauge reads 170 then something is awry. Could be anything - previous owner added a resister because he got nervous seeing the temp gauge over to the right, your sending unit is slowly dying, the sending unit is located somewhere where it sees cooler water, or ??

I do believe that running too cool increases wear on your engine, and do believe that 160 is too cool. I would change the thermostat and investigate your temp gauge problem so that you have an accurate idea of what your engine temp really is.

The sending unit should really be located in the plug on the block and not the stock location on the overflow tank. You want to know what the temp is in your block, not in some external component.