Agreed.

 

When you switched themostats, did you use a performance one, like MR. Gasket? They work a lot different than the stock ones. I did that on my '88 and it made a decent difference. The best single change I made though was the electric fan swap.

 

If it were a tired fan clutch, it would heat up at idle and then cool down once you were going down the road. Personally, I see nothing wrong with an idle temp of 180. The going down the road temp is high. I'd say bad rad or water pump. Maybe even something as simple as not having the little black plastic air dam in place. A lot of guys take those things off for looks only to find out it's there for a purpose...to keep your engine cool.