Check IR on the T stat housing.
What is your fan switch at? should be turning on no later than 180 ( napa has lots of choices, I spent many years fixing 3rd gens this way)
need to keep that tranny under 200 for sure.
You could easily run a 160 T stat as well, keep in mind that 160 is "static", it starts to open at 160, its not FULL open till 170-175. ( dynamic)
once full open the heat exchanger(radiator) and capacity determine your temp with circulation.
Your set up( 9.5 to 1?) with a clutch fan and a 4 core on a 80 degree day should be able to sit at 182-187 idling. youll still be over 200 in the combustion chamber, for efficiency.
hope that helps
