P/S box question

According to the parts book, they used 2 different boxes with power steering..

# 3643013
73-74 Barracuda,Challenger, Charger,Coronet,Dart, Duster, Satellite,and Valiant,all models except police cars.

# 3579526
73 Barracuda,Challenger,Charger,Coronet, Dart,Duster, Fury,Monaco,Newport,New Yorker,Satellite,and Valiant.

Identify this unit by the letter "A" stamped on the date tag in place of the numeral "3".

Hope this helps.