I agree on the High flow thermostat. Pretty sure there wax filled. Work good. The stock wp pulley will help at low rpm.(they made the ud wp pulley to work the factory belt).
You didn't get the wrong direction wp by accident? Or a bad wp.
The only time I get to 230 is at the drags in the staging lanes. I have 190 stat, UD pulleys, electric fan(No shroud),stock rad and wp.
------------------
82 Mercury Capri 302.
Comp. Cams
Tremec 3550
3.73's
12.8@106 N/A
Kevin's Capri