I used the CD2 and would not recommend  it .   When I used it in my '85,
it almost shut down my motor and I had to limp home.  I immediately started
checking out everything else, FI, ignition, fuel filters...   The lifters
were collapsing after about 20 to 30 minutes of interstate driving.  The
lifters would start clacking and I literally had just enough power to get
home.  After I changed the oil, it never did it again.  The guy was right
about crud in old engines, you don't want to cut it loose all at one time.
If you go the ATF route, I would only use 1 pint or less with your oil. (I
have heard great things about the Marvel Mystery Oil, but have never used
it. )  I ended up replacing all my lifters and I still get some noise.  I
think it is inherent of the horizontally-opposed engine design.  Corvairs
are the same way and we used to run a pint of ATF all the time.

                                                             Jay