Different 3-speeds

There were four 3-speed transmissions produced and installed in A-bodies in the 67-76 time frame.

1. A-903. 67-72. No synchromesh on first gear. Drain plug on drivers side towards the front of the box.
2. A-250. 73-74. No synchromesh on first gear. Drain plug on drivers side towards the front of the box.
3. A-230. 70-74. Fully synchronized. Removeable side plate with shift forks.
4. A-390. 75-76. Fully synchronized. Rib cast on outside of box between the shift fork shafts. No drain plug on drivers side.

Hope this helps.