We do have a comparison pic of the older adapters on our
Understanding the Success of the Marlin Crawler page that needs to be updated to the new site theme:
MC01 (1994-5), MC03 (1995), MC05 (1995-96), MC07 (1996-current)
The MC01 was awesome because it is compatible with any shift-style transfer case
We still have MC01 serial #2 in Visalia. He drove it through the Round-Up last fall!
