Need Help Runin hot!!!!!!

I have a 87 5.0 speed density......

for some reason lately my cooling system is runin real hot it was fine with 190 stat....just replaced with 160 stat......
for a while the engine runs at two bars from botton of factory gauge then once I sit there it goes approx 50 deg hotter...and my exhaust it scalding hot...there not glowing but hot enough to flash boil water on it..so it heats up the floor....

I just recently passed emissions with flying colors same as last year this being during my heating problem....doesnt not seam like any restrictions in exhaust...
at idle you can see the coolant moving a little in the radiator and goes down with accleration......

I need any thoughts on my situation....

it cools down at speed runs hot at idle....I havent figured out if it just cause of how hot it is outside?

but the exhaust is hotter than normal cause my floor wouldnt get so hot from the exhaust.

but my cooling would stay at one temp easily and now when I stop it goes up and the engine bay is hot as hell.

I have a autometer temp gauge just haven't installed it yet so I'll hook that up andsee what it is

where should I hook the vacuum gauge to???