Here is something I dug up from ls1tech.

"Use the speedometer items from a 3L80 (3 speed trans) truck, part numbers were previously posted (GM# 8655291, 8655315), they work perfectly on ex-A4 cars. Just cut the (will verify wire colors) wires and splice them to the connector (p/n: 12085498) "


You can also use a wheel speed sensor to do this. Take a look at the stickies on ls1tech and most of the the info is there if you take some time to sort through it. Hope this helps. Vince

 

How hard is it to swap to a 400 trans? I want to do this to my truck?

 

Use a tail housing and reluctor and VSS sensor and VSS Electrical connector from a 1988-1990 3/4 chevy pickup with a big block and a th-400. Remove the mechanical speedo parts from the tail shaft,,, heat the reluctor up with a torch to make it expand and then slide it onto the output shaft. Install the tail housing and sensor splice the new connector into the existing harness and you are then good to go.

a 1998-1990 c-1500 with a 4.3 v-6 and the 3 speed tranny option which is a th-400 will also work if you look it up by application

 

I was going to use one of these in the drag/street Camaro I built for the ex.

http://www.dakotadigital.com/index.c...rod/prd109.htm

But in the end taking the signall from the front wheel sensor was the easiest route.

 

Some part numbers I used when I did the TH400 swap on my old "LS1 TRK"...



12551367
Engine Flexplate

24232618
Speedometer Drive Sensor

8655315
Speedometer Drive Rotor

12563532
Engine Flexplate Spacer

12563533
Long Flexplate To Engine Bolts

I'll try to find a part number for the pigtail.

 

Anyone have one of the VSS sensors on the right in the picture?