[hound dog]

Gary,
Another thing I found out this week after going a round with my engine machinist on internal vs. external balanced engines. If you have an externally balanced engine, and you probably do, the counterbalance weights on the harmonic balancer and the flywheel must be indexed together (aligned). Evidently the weights are used to ofset the throws on the crankshaft when balancing and if you index the flywheel wrong you can upset that balance. If you have the weight on your harmonic balancer you have to have it on the flywheel. Just another thing to check if you do a teardown. Have fun and post the fix!
H Dog