[68c10airstream]

Hi Leon, obviously this is for 2wd. First you remove the original extension housing, take a metal cut off wheel and cut through the vss sprocket ($9.00 list part) and remove it. Now slide the sleeve (in the middle of the pic) up the mainshaft with the sprocket end forward. Assemble the adapter to the trans body, install the new extension housing and install your driveshaft. Now you go through the speedo cable adapter hole and position the sleeve where the corkscrew end is centered in the hole. Put locktite on the allen socket set screws to hold the sleeve in place. Now for speedo calibrations. Shiftworks can look up what you need for the plastic gear needed on a chart (this is included and mine i will have to double check, i believe 37 tooth) and what is called the adapter. The adapter is what holds the plastic gear into the extension housing. There are various adapters, each one has a range. Mi adapter i think is for 35-39 tooth range. I was running 26.5" diameter tire with 3.08 axle ratio. This adapter and plastic gear set-up was in use from the 60's till the early 90's so parts should be readily avaliable. Thanks for the interest.