>always had a bad vibration
Fords often have driveshaft balance problems, very common, and more likely than other issues. It is hard to get the pinion angle so bad that it affects anything unless you are building a race car.
The only real complication for a truck it that the axle position changes when the truck is loaded, cars don't move up and down nearly as much.
But really , all you want is as straight a line as possible, perfection would be that the height above ground, with the truck loaded (the engine in) where it is normally driven, is the same at the balancer, trandmission tailshaft, and axle pinion. In practice you can't do this, so you go for as straight a line through 3 points as you can. The problem that is hardest to fix is the angle at the axle, because truck axles aren't designed to be rotated....So instead, you have to move the engine up or down, and then you are stuck with motor mount issues, so instead, you angle the transmission end so it points at the axle...and that's often the best you are gonna do...
(Do however, make sure the engine is true side to side, that problemwill cause all kinds of weird things to happen...)