Well the 3.8 is externally balanced meaning the flywheel has a weight on one side.
I tool the original flywheel and put it along side of the new flywheel on a rod that fits in the center hole.
I then turn one flyheel 180 degrees from the other.
Then i used the forkes as leveling rails, found the heavy spot of the two flywheels that are bolted together . And i just kept drilling a hole to remove weight from the heaviest point. Untill there was no heavy spot. So the new flywheel was countering the old flywheel .
And thus i have a flywheel that is balanced the same as the original!