I have a 1988 Firebird, originally a 2.8 V6. I am doing a complete drivetrain swap, putting in a 305 engine and tranny from a carburated 84 Firebird. Problem is, my 88 has an electronic speedo, the 84 tranny has a geardriven speedo. Anyone have any ideas how to overcome this problem, and get my speedo to work?

 

Just use the electric sending unit that installs in the tranny. The only problem is that the gear inside the tranny might be different then what you had. You will need to change the gear if the spdo does not read correctly.

 

So all I have to do is unbolt the sending unit on the end of the V6 tranny and swap it with the V8 one, and I'm in business? That sounds almost too easy to be true!

I hope all the other problems I will encounter with this car will be that easy...

 

As long as both transmissions are the same kind, either 700R4's or T5's, the sending unit will swap over. If you are swapping an auto for a manual (or manual for an auto) you'll need to locate the appropriate sending unit to fit the 84 trans.
While you have the sending units out, compare the colors of the drive gear (the one that stays inside the tranny); if they are the same color, you won't need to swap the gears to make your speedo read correctly.
Good luck ,and have fun!

Pete