You've got some L-series Cast Iron transmissions.
If it has some linkage on the side, its a 4spd L43, otherwise its either a L45 4spd or a L50/L52 5spd. They are from 79-83...
Now a W56 is 4 inches longer and the only cast iron piece is its center section, with both opposed housings being aluminum. The W56 came in two different versions, (1) from 1985-88 EFI 4cyl and the (2) other from 1989-95 EFI 4cyl. The (1) early one used a top shifting t/case with just one lever on the top, and the (2) later one used a forward shifting t/case with two levers on top, transmission and t/case levers.
Both W56's bellhousings are detachable, unlike your cast iron trannys.
The shifters are different as well. Your L-series transmissions use a push-and-turn style lock (like a turn single lamp) while the W56's use a 4 bolt base plate.
Regards,
BigMike
