12 valve over heating

1996 12valve over heating
need some help, I installed a new Mishimoto intercooler to get my egt,s lower last spring , and since then my water temps run at 230 when towing hills. I tow a 40 foot toy hauler weight around 24,000
I replaced water pump , new thermostat oem ,new fan clutch , new radiator ,fan shroud is is great shape. and at the moment there is no ac condenser installed
I have compounds and afc live, turned my fuel down till I was only pushing 20 pounds of boost and egts was at 938 still ran hot, no coolant is pushing into the overflow bottle.
is it a possible head gasket ? you would think when im pushing 65 psi boost it would push coolant into the over flow but its not.
any one have any ideas ?

What does the coolant look like

Have you checked the temp with an infrared temp gun? You could have a bad sensor or gauge. Your ECT sensor is at the back left of the head. Or, you could install a mechanical gauge for diag.

coolant is clean no oil and no coolant in oil

Will the fan suck a rag to the radiator?

Blow the rad out and flush the coolant system?

Is the intercooler blocking flow?

I'd do what BigPapa recommended before I got knee deep in it. These old gauges on the dash ain't always accurate.