Double post

Maybe try a cooler thermostat.

'technically' the thermo fans are only needed on idling or dropping revs after a big fang. if your radiator doesn't keep things cool on the move, then you need a bigger one. if you had a little rx7 rice burner with massive turbos wedged in under the bonnet then you have problems, latish falcoons have a good airflow thru the radiator thanks to problems with previous models.
and yes shrouding and undergravel trays do help, but shouldn't be necessary.