I am doing a engine and trans swap on a 1989 rs. I am switching from tbi to carb because the wiring is trash. what i need to know is do i need to switch the speedometer over to a older cable driven or if i can use the stock one which is electric. if i can use the stock one do i need to rewire it? If i need to rewire it how is that done? I know It would be easier to switch everything to cable driven but I want to use as much of whats there as possible.

 

You can get a VSS sender that screws into the speedometer drive and hook that into the original wiring.

I assume the TH350 in your userinfo is the tranny you're talking about. Out of curiosity, why are you swapping that instead of sticking with the TH700R-4?

 

I had it laying around and i know its good because i rebuilt it a couple of months back. for some reason I keep going through 700r4s in my truck. so screw it 350 th it is.

 

only if your car has the yellow VSS box in the passenger side dash will it work. just using the VSS off the trans by its self will not make the speedo work. because you are doing away with the ECM.
I have a Big block in my 91 and I had to do this also. there are threads for this and pics for the wiring. its really simple.