4 inch lift front ,old springs rear- how high

[mdshore]

i measured the front from the bottom of the frame to the top of the dana 30 , 11 inches on the dot. the back is currently a saggy 10, im just starting to see spline on the driveshaft .. what size springs should i get , and should i shim it for better angle.. ? lengthen the driveshaft im assuming ill have to.
it is a duff coil front. im not sure how much the leafs will settle in on 3.5 or 4.5 leaf kit, especially since ill be running mostly soft top , no top.

 

[broncnaz]

With a soft top you can probably just get the same height as the fronts. A few of the venders recommend getting 1in taller ones when you run a hard top and carry toools and such. Shiming teh axle will help pinion angle and extend ujoint life.
The thing you have to worry about with the drive shaft is if it come apart during full droop basically its probably a good idea to get a new one that fits correctly.