[69 longhorn]

I think you can use a slip yolk from a 400 turbo for that app. a couple yrs ago,I got a drive shaft from a 90s GMC that was marked as from a 5 spd truck. I used the shaft in my V8 chev powered ranger(had to use conversion joints,& change slip yolk)......but the 5 spd yolk was slipped into a 400T to keep from spilling the fluid. i never did "mike up" the 2 different yolks,but the fit felt ok in the trans. Un fortunatly,i dont have the slip yolk anymore to get dimentions from ......69 longhorn.