Ford 460 motorhome running hot

Glad you got the timing straitened out. 200 F on a flat and 220 on a hill sounds normal to me for an older 460. I would do several things to reduce the heat. Remove your thermostat and put it into a pan of water and see if it opens a 1/4 inch or so. I have seen several new ones only open 1/8 inch. You can use a good chemical flush in your radiator and drain before you remove the thermostat then reinstall the housing and flush the radiator from the lower hose using a garden hose. Without the thermostat in the way you will flush the whole system and see a lot of mineral deposits come out the drain. Also you can check you radiator before and after the flush with a IR gun in a grid pattern every 2 -3 inchs from top to bottom. When radiators clog they seem to clog in the middle and much colder readings would indicate a clogged section. You should see a delta T of 40-50 degrees F from top to bottom on a functioning radiator. There is a viscous fluid inside the fan clutch and if it leaks out it will not engage the fan. Look for leakage on the clutch also clean the spring in the center of the clutch on a 1988 it is probably covered with dirt which insulates the bi metal spring which controls the fluid into the clutch as the air temp rises. The fan blade should spin by hand with some resistance. There are other things to try but try these things first and let us know how you make out.