Crank it up, and warm her up.
Turn the idle-speed down to ~750rpm, or whatever the engine is comfortable at, but not less than 700, and not less than 10 psi oil-pressure.
now we wait.
Now then,
Keep your IR gun handy.
Keep running water handy, in case you have to mist the rad.
Start it up with the Rad cap off.
Watch for when the stat opens, to see the water begin to circulate.
Watch to be sure the rad is not breathing toxic fumes.
At 200* you can reinstall the cap.
Keep your eye on the temp with the IR gun.
While you got the IR gun there, measure the temp of the water leaving the rad, at or near, the lower hose-nipple, on the METAL part, and compare that to what is going into the rad. The difference should be ~30 or more degrees.
IF YOU do not have that 30 degrees or near to it, STOP!
Something is wrong. Figure it out,
either the water is not circulating, or the fan is not pulling, or the rad is not efficient enough, or the engine is creating excessive heat, or the coolant is not doing it's job, or the belt is slipping; figure it out..
Here is what I shouldda done;
Take all the sparkplugs out,
Take the rocker gear off,
Put the trans in Neutral.
Take off whatever you need to, to get a Torque-wrench on the Balancer bolt, and lets see how much drag the rings are producing.
You can do this now, or you can do this later after you have spent a thousand dollars and and 30 hours, racking your brains on why this is happening to you; or more.
If you don't do the above, which I didn't, then;
Install an 8-vane Pump with an anti-cavitation plate, with a Hi-flo thermostat.
Install the biggest daymn steel fan on there with a Thermostatic Fan-Clutch, inside a shroud, on an overdriven pulley, and get the fan up into the shroud.
Take the bypass hose off and plug it. Then re-install it. Let your heater be the new bypass. If you don't have a heater, then go back to the bypass hose, take the plug out, and install a restrictor instead, one that cannot migrate nor turn sideways.
Install a new belt, and tighten the heck out of it.
Take your Power-Steering belt off.
My problem ended up being too-small ring-gaps, on hypers.
I took the engine out, sent the block out to hone another half a thou into it, then bought a set of File-fit Plasma-Moly rings, and put the tops in at 034 and the seconds at 030. Badaboom, INSTANTLY, my overheat was history.
I took off that big direct-drive fan, in favor of a clutched fan.
I took off the overdrive pulleys and installed slightly underdriven.
I installed a 195 Hi-flow stat.
I retarded my timing to 5*, which dropped my Idle-speed to 500/550 in gear, to parade the car at 3.5mph with a manual trans.
I took the water out, in favor of 50/50 antifreeze.
That big T-clutched fan keeps her at exactly 207*F no matter what the engine is doing.
Midrange-Power went up.
Fuel economy went up.
Idle was stable.
The hole I cut in the hood to deliver fresh, cold, air to the 750DP, was now redundant; daymn! cutting that hole just about broke my heart.
Here are some other things that need doing on your combo;
Do a compression test.
Fix your IDLE-TIMING.
Sync your Transferslots.
Fix your Power-Timing
Fix your Stall-Timing
Calibrate your VA,
Forget the Electric fans.