68 c10 L6 engine vibration problems

[davepl]

Originally Posted by Shaky

You're sure that the outer ring didn't spin relative to the inner? I'm just asking because it has happened to me on a 6.

Wouldn't this show up on a timing light pretty quickly? I suppose it could slip only a couple of degrees and that'd be hard to diagnose, but anything more than about 20 degrees would put you so far out of whack that if you set your timing based on the timing mark you'd have really incorrect timing, your rotor would be out of phase, and the engine would shake bad. Just like this guy's truck :-)