70duster 360 gets hotter the faster i go

This is what i got
70 duster
The engine
360 punched .060 over with kb-107 pistons, comp thumpr cam .497/.483lift, 235/249 duration @.050, 107 lobe separation...comp cams pro magnum hyd lifters, and ultra pro rockers set at zero to 1/8 turn lifter perload....oil mods to block, stock 360 heads with 1.88/1.60 valves and open chambers, air gap intake with holley 750 dbl pumper (mechanical secondary) MSD 6a box with MSD pro billet dizzy, MSD blaster2 coil, MSD wires to champion copper plugs gaped at .040.... Headman headders to 2.5 exhaust to the bumper
Timing is set at 22deg idle/36deg all in about 2000rpm, no vacuum advance

The tranny
727 with a mild shift kit and a b&m 2400 holeshot converter

Rearend is 8 3/4 with 3.55s and a eaton tru track with moser axles

The cooling

Right now im runnin a 26" 3row radiator out of a 77 powerwagon... Its new, last brass one my local auto store had...a stock style 8 blade pump (mayb gmb makes it?) dual 12" spal fans (3100 or 3600cfm, i forget), and a high flow mr gasket 160 stat..and it has a good spring in lower hose...in front of my radiator i have a big tranny cooler off to drivers side (no name, it was in my parts pile), and a b&m supercooler engine oil cooler (the biggest one i could buy)
I can blow compressed air threw the grill and it makes it to the engine threw the radiator no prob

Ok i think i covered it all... Hood has a rubber seal in front and in back both in good shape... 1st off, im running my fans 100% whenever it hits operating temp (toggle switch inside, ill put sensor in after it runs cool)will idle all day right on 160..... So in town driveing it will start to warm up a lil 180-190, and thats perfect, if it had a 180 stat...but whatever, keep cruzin along, mayb around 40-50, temp starts gettin up to 210-220... I hit the highway jus for one exit, 235deg! As soon as rpms drop, give it 5min and temp will b down too

I have tested my thermostat in a pot of water, it opens wide and starts opening at 160, i have tryed a standard flow fail safe stat, and it got hotter quicker... B4 my electric fans, i had that low profile clutch fan, electric fans cool it down alot quicker (no shroud on clutch fan), but this seems to be a high speed problem... Also, the spal fan i have has flappers on the shroud, so when it gets airflow threw the grill, they all flap open and it gets good airflow

So only other things u can think of is a flow kooler pump, and if that dont work then mayb a cc374 radiator??.... Mayb an air dam under the bumper??

What do u guys think?? Am i missing something?? I tryed to put as much detail in as i cud think of, if i missed something, please let me kno

Thanks guys!