Quote Originally Posted by dave w View Post
I think a 4K VSS is a very poor option because the Speed Pulse Per Rev number will be extremely low. The 8K VSS already has a low Speed Pulse Per Rev number and is likely the lowest cost option too.
4K still works ok provided you are not using an electronically shifted transmission. I used the stock 4K one in the cluster on the 87 G20 with the 6.0L and a TH400. Worked well enough to run the IAC logic and DBW cruise control.