Are the 83 and 84 e-shafts the same? I have a running engine from a 84 GS MT that I'm trying to put into my 83 GSL AT. When I tried to put the weight/ flywheel from the auto onto the 84 motor, it didn't fit up. The only reason I can think of id that the back end of the 83 e-shaft is different from the 84.

 

All Rx-7 12A e-shafts are the same. Make sure to remove the e-shaft needle bearings when using a manual engine with an automatic trans.

 

Derp, it was indeed the bearings that prevented the torque converter from going in. Already ordered a new clutch though, so I'm gonna throw the MT in.