I have a small block 355 engine that was rebuilt about 1500 miles ago. It has headers, a medium cam, forged pistons/rods. It has double hump heads, 650 CFM holley etc. Saturday, I turned off the ignition and the engine kept running for a couple of seconds, kind of dieseled. I heard a strange clunk noise, it sound like something from the back of the engine.

I restarted the engine and when I did, I noticed the starter sounded a little odd, like it didn't mesh just right. Then at about two different rpm's, around 1000 and again around 2000, there is a vibration that was not there before. After starting a couple more times, the starter engages but does not turn over the engine. I can tell the starter has power, because when you place in the start position, it dims the lights.

Do you think something could have happened to the flex plate? Broke loose maybe?