69 Dart cooling questions

I'd do like jefflock says & try a 180 thermostat if you haven't already. Sometimes a 160 can let the water through so soon that the radiator doesn't have a chance to do it's job. I'd also get rid of the pusher (it could be blocking airflow) & switch to the Mopar viscous fan setup. And I agree that that radiator & shroud should be adequate.