Here is a response from Jerry:
THEY ARE ALL INTERNAL BALANCED , THOSE BALANCERS /DAMPNERS DONT GIVE THAT MUCH TROUBLE UNLESS THEY HAVE BEEN PULLED ON BY THE WRONG PULLER, YOU NEVER WANT TO PULL ON THE EDGES ,
IF THE VIB,S YOU ARE TALKING ABOUT ARE THE KIND YOU CAN FEEL IN THE STEERING WHEEL OR BODY , YOU HAVE MISLOCATED ENG MOUNTS , VERY COMMON, ON THESE OR THE MT,S HAVE COLLASPED , I HAD THE SAME THING ON MINE
Then I asked him what he meant by mislocated mounts:
THE FRT MOUNT S SOME TIME CAN GET TO SAGGING OR TWISTED , AND THEYA ER HARD TO SEE , BUT TAKE A LOOK AT THE FRT MOUNTS WHERE THE TOP PLATE IS BENT OVER THE MOUNT ITSELF , IT SHOULD HAVE A GAP THERE THAT YOU CAN STICK THE ND OF YOUR FINER IN BETWEEN THE TOP PLATE AND THE MOUNT ITSELF, I BET IT IS SAGGED AND TOUCHIONG USUALLY IT IS THE PASS SIDE BUT THE DRV SIDE CAN DO THE SAME, THE REAR TRANS MOUNT SHOULD BE THE SAME WAY TAKE A LOOK AT THE MOUNT AND THERE SHOUDL BE AT LEAST A 3/4 IN GAP BETWEEN THE UPPER AND LOWER PART , IN THE MIDDLE OF THE MOUNT , THIS ONE CAN BE FIXED , BY JACKING UP THE BACK END OF THE TRANS AS HIGH AS YOU CAN GET IT AND PUTTING A PIECE OF FLATTEN 3/4 IN HTR HOSE IN THE MIDDLE AND THEN LET IT BACK DOWN, THE FRT CAN BE DONE THE SAME WAY BASICALLY BUT IT IS HARDER TO DO , NOT VERY MUCH ROOM TO WORK WITH
(he's not the best typer lol)