^0 series with 1hz turbo still overheating

Hello to all, well since last time I was on this forum I have tryed a lot of different things to fix my over heating problem removed new thermostat but it still gets hot under load and up hills I have made scoops to direct the air flow better into the grill erea I had West end deisel check the fuel sysem & correct the injector pump timing they have done my injector pump up & fitted a boost compinsater to it,when the cruiser went on the dyno I had 84.7kw at the wheels & 513nm @4000RPM but they said it was running very lean up top, since there mods it now has 99kws @ the wheels and 560nm @ 3200RPMS and you can really feel a big improvement all round BUT the B*#!#* thing still gets hot on the hills, its fine around town and just cruisin on the freeway but if you punch it along a bit she starts heading for the red I have been in touch with a guy called Norm (Aussie Desert Cooler Radiators) he said my 60 series Radiator will never cope with the 1hz with a turbo he suggests a 5 core triple flow he said its the biggest that will fit in without modifications my Radiator is a 4 core I have done the silicone oil in the cluch fan (2 tubes ) and even put a 16 inch Davis Craig thermo on instead of the clutch fan and with the clutch fan also infront of the radiator still no luck also had the compression checked and had the die guage on top of the radiator alls ok the only thing I havnt checked is the water pump I dont really want to pull the timing belt off again etc etc so I was hopeing the bigger radiator will solve my problem im just a liitle bit over this over heat problem (spent over $2500 trying to solve it and funds for this truck are running thin! any feed back would be appreciated thank you all Cheers Scott