I have a 68 camaro with a zzr and 4.11 gears. Yesterday I was driving on the freeway at 3500 for a couple minutes and the car got to 220 degrees which it never did before even at that rpm. It always stayedaround 180 on the street or freeway. Then when I came to work this morning, which is only like four miles from my house, the engine heated up real fast but then cooled a little as I was stopped at lights. It did this hot cold cycle a few times then stabilized at about 180 as I got to work. It never overheated above 180 but it has never jumped around like that. I do not know what the thermostat is set at. Did something happen when it overheated? Could it be the cap or thermostat? Please help it my daily driver and track buddy.