I just put a '69 Olds 455 in my '86 Camaro, (that was a job), before I took it out of the other car it ran fine, didn't smoke or anything. Then I put it in my car, got it all in there nice an pretty and finally got it running. The first couple of days of playing with it and adjusting everything it was fine. Was taking it to a car show. Got up that morning for the car show and it smoked like there was no tomorrow. Come to figure out one or two of the rings blew.. Now how in the world would that happen. I replaced all the fluids before I even started the damn thing. Did not even get a chance to stomp on it or anything so I just don't get it. I am going to rebuild the motor but I would like to know what happened so I don't do it again. Thank you for your help.