OK, crawled up under the front end of the car and took a close look at the balancer.
In short - it's JUNK - no two ways about it, it needs to be replaced.
Rubber on one side is mashed out over 1/8". Last short test run, the thing is being thrown out so far to one side from the center of rotation, that if it isn't replaced soon I have a real concern it's going to take out the timing adjustment pointer.
That's in addition to the swashplate-type motion it's making.
Google search on the Mustang forums, for cars of this era, seems to be a common complaint - not so much mileage but age - the rubber just gives out. And of course, the way it's sleeved and keyed onto the crank, you have to replace the front main oil seal as well.
Doesn't say much for Ford's engine design, when the stock balancer needs a 50 ounce counterweight to make the engine run correctly. Entire balancer weighs over 9 lbs just by it's lonesome.
This, and all the other crap I'm running into going over this beast, is vividly reminding me why I haven't personally owned a Ford since 1987.
