ok, i have a 89 cutlass ciera with a 2.8 and i am planning on get a 3.8 super charged III to drop in it. now i am not sure if in need to change my tranny, and i do i am worried about get halfshafts to fit to my car, any input in this would be great. thanks.

Welcome to AF !

It not going to work very easy, if at all !
You would need the 3.8 trans, the PCM, ECU, BCM, and the engine wiring harness for the 3.8 , you'll also have to piggy back the computer(s).
Then thiers a matter of getting it to physically fit under the hood.

More trouble then its worth IMO.

Good Luck!