The VSS you will need will have to be the style that was used in the 84-86 Berlinetta, (most) 86-89 Firebird, and similar year Corvettes. Your tranny should currently have a cable operated Speed Sending unit in the tail-shaft,... this will need to be removed and replaced with the electric version of the VSS. There are at least 3 versions of this VSS

1 Version is for T5 cars
2 versions are for automatic cars.
** Electric VSS 'DRIVEN' Speedo gears are NOT THE SAME as Cable Speed Sending 'DRIVEN' Speedo gears. ( all 700R4 Tailshaft mounted 'DRIVE' Speedo gears ARE the same. )

This picture shows you what the electric VSS you need will look like:

NOTICE THE DRIVE Speedo gear tooth range,... only 40-45 DRIVEN GEARS will fit properly on this VSS. If your rear-end gearing requires you to use a SPEEDO DRIVEN gear with 39 or less teeth than you will need the other version of the electric VSS




P.S. You will also need to add a VSS Buffer Assembly as well as wiring from the VSS to the Buffer and wiring from the Buffer to the Cluster.