what are you using for a thermostat ????get your self a mr gasket or other name brand,,jegs/summit/local speeed shop get a high flow 160 degree and try that,,, how many rows in that rad ???
A 160* thermostat WILL NOT fix a cooling problem...it might make it worse. A thermostat will only effect coolant temps if it sticks closed other that that it has no effect on max temp. That is determined by the radiator, fan, water pump and other engine factors.
Sounds like you are going through what I did a while ago. Ditch the FlowKooler pump...they suck. I bought into the hype to and it is BS. Get yourself a stock replacment pump from NAPA or someother parts store. Get an 8-blade unit for a HD cooling system from say a 3/4 truck with a 360. Then put a Mopar Viscious fan on there and say goodbye to your cooling problems. Mine rides the 180* thermostat all day long now even in 90+ temps.