JSUAVE

I have a stock 66 coupe with V6 it has been running fine due for an oil change though. Last drove four or five days ago ran fine filled the tank up parked her in garage. Went to take her out and she cut off when I put her in reverse did this three times. Was steeming heavily I changed the oil and the air cleaner it was filthy still steeming/smoking. Guage is leaning toward hot after only running 4 mins about to check coolant level after that Im lost. Just had the AC cheked a couple weeks ago thats why I never considered running hot could be a problem. Any suggestions