i put my newly assembled 8.5 posi in my 69 skylark today.the questions are as follows.how much drive shaft slack should i have?i twisted up my stock driveshaft and the one i currently have is from a 71 grand prix.some guys say a 8.5 requires a shorter driveshaft some say it doesnt.before the rear swap i had plenty of shiny yoke showing when the car was on all fours.does anyone know the u joint to u joint measurement required?i need help from someone who knows...thanks in advance............dave
All I know is you need 1" of shiny driveshaft yoke showing. Yes, the driveshaft is shorter.I think(not shure) that any shaft from a 71 & up, A body car with an 8.5, will work.
Length may also depend on trans type as well. They were all color stripped coded from the factory so assembly line workers could tell them apart. Were several codes each year indicating many different lengths. Assembly manuals give colors and lengths. your best bet is to go to a driveshaft shop and have one custom made. Cost me about $200 I think. used ones are often out of balance.
