unless you put on a big bore kit, the 06 engines would be the twin cam 88's. It was a good engine in my 05 road king, but not nearly as good as my '17 with a M8.
I wonder why the twin cam 96 would not work?
The 96" Softail motors are of the later version when they went to the Cruise Drive transmission. The 96" has a 5-bolt primary pattern that will NOT fit the M3W adapter bolt pattern. Also the crank on the 96" is a full external spline with an internal bolt versus nut type crank retainer.
I do have an '05 CVO 103" that's a "B" motor with counterbalance shafts. Again, only the Softails had the counterbalance shafts. There were several different versions of the 103" in the CVO's prior to '06, but only CVO Softails had the 103". The '03/'04 CVO Deuce had a 95" counterbalanced motor.
