I have the A833/MY6 installed in my 63 Chevy C20 with a 292, and love it. Haven't had a chance to put that many miles on it yet. I have 4.10 gears in the back, and the gears are great, much better than the SM420.
The shift pattern is the same as all other 4 spds with the exception of reverse. Reverse is as stated left and forward. Had to shorten the drive shaft about 9 inches.
Larry