[68c10airstream]

I'm running an 85 c-10 gearbox in my 68 ls swap and it's my favorite box because it's 3 1/2 turns lock to lock, and the best part is variable ratio.

You just need to match up your lines. The 85 box is oring style and there are adapters to use inverted flair with these adapters into an oring box.

Another way is to use the 85 lines and just change to an oring (85) style screw in fitting into the back of the 67 pump.

Your rag joint may need to be changed to match the 85 box to your intermediate shaft or get an 85 intermediate shaft and rag joint. Don't give up, once you drive it, you will love it. The gm engineers really did a great job on the variable ratio box, the best of both worlds. Slower response in the center straight ahead position so it's not twitchy, and after turning past 1/4 left/right it responds quicker. This gives you casual highway driving with sporty response when needed. A quicker box with less turns is perfect for autocross, but when a few friends drive my truck a typical response is " god that drives nice"," I don't believe how good it handles, just right"

I went to auto schooling in the late 70's and rebuilt these box's and still love them!