Ford AOD

Looking for an AOD to put in a 351 /51 Ford woodie I'm building... Are there any particular years that are better? I know I've heard to use a truck AOD , but what I'm wondering is what are the identifying codes on the castings that tell what year is what... anyone know?
Thanks,
Barry
first time posting here in a L-o-n-g time

Barry,for the best info on Ford AOD's go to the Ford Transmission forum at www.network54.com/forum/260730/ 88-93's are the best years they have all the upgrades and are non-computer.