I I just recently purchased a 93 Explorer sport 5 speed and changed thermostat but it is still overheating, flushed out radiator still temp gauge rising.

 

You may have a head gasket problem and or a crack in one or both of the heads. Check for milky oil on the dipstick or try to look in through the fill cap on the valve cover for the milky oil. The best way to check is to remove both valve covers and look for coolant mixing with oil. The early 90's had problems with cracked heads.