[Tim Brewer]

Do you have a Hyd. T/O bearing? If you do have one and if it was leaking on the disc, that would cause chatter. If your bellhousing is out of alignment,that also would cause chatter. Also, your mechanic is right about your rear end being high, a 288 is WAY too high in my opinion. You car would be much happier with at least a 3:50 or even beter a 3:73. Right now you're geared to top out something like 210 or so. Is it kind of tough to cruise across a parking lot in 1st without the car wanting to buck and jerk?
Good luck,
Tim