why did it over heat in the first place? change the thermostate and i think it will be fine. when you first start her take the top off the expansion tank/res and if the water is fllowing / pumping around the system its the stat. good luck.
:)hi had a vauxhall once with a miss fire and the cat glowing red hot.it was the h/ t leads and the top chian part on one of the plugs had a hair line crack down it good luck.