hello i need to order some trans parts for our66 but iam not sure what trans we have i have the numbers from the tag off the trans and would like to know if somebody can tell me what they mean there are 2 numbers on the tag the number on the top is
-pcw as- and the number on the bottom of the tag is -289 6c 28 b4- any help would be greatly appreciated thank you

 

That is a C4 automatic Dual Range XP transmission used in 1964-66 Mustangs. That particular transmission was behind a 289 V8 and was built in March of 1966.
You can see the listing for the C4 (PCW) here and the 289 is the CID of the engine and the 6C represents the year which is 1966 and the C represents the month which is March.
http://raceabilene.com/kelly/hotrod/...ns/fatlist.gif

 

If your local auto parts store says their catalogs or computers do not go back to 1966, you may be able to use 1967 on up parts - note 'may'.
Jim