I was out racing my car last night and all of a sudden it started shooting smoke out the tail pipe. when I saw this I let off and pulled over and cut the car off. checked everything and it didn't look like the headgasket was blown or anything so i let it sit for 10 mins then started it up. lightly smoked a few seconds then it was ok. I drove the car home and it didn't smoke once. I'm thinking my rings are shot. I have a spare motor in my garage and I have a headgasket kit. I'm thinking if I should rebuild the motor that in my car or rebuild my spare motor and drop it in. What do u guys think?