Currently my truck has stock springs, and a 3" body lift. 1990 GMC Jimmy, 350/700/241/3.73's 1/2 ton. I have an ORD shackle flip kit for the rear. If I gather my information correctly, I shouldn't need new drive shafts? At least for the time being, IE they will physically work. Also has anyone had any vibration problems after this, as this obviously changes the pinion angle in relationship to the t-case angle. And if I'm not mistaken, for a smooth ride those angles (ie u-joint angles) are supposed to be the same within about 1 degree. I wanted to do a 52" spring swap up front. Looks like a bad ass way to do things, more flex, more lift, and on the cheap. If it moves the front axle forward, should I have any problem with my 35's contacting the rear of my front fender? As you can see the axle doesn't look very centered any more after trimming the fang on my truck. Here is a picture of full stuff. If I were to turn my wheel to the left, it would basically touch the inner fender and try to push the outer one off the truck. And this pic is of a worn MTR, so a new one would be contacting the inner right now. So between being moved I think "they" say like 2 inches forward (which would solve this problem as I see it right now, so even zero rates could do this) and the extra 4" up, I shouldn't have any fender contact? I just don't know how far back the 52" setup shifts when under full stuff. I'd also have to assume it actually doesn't stuff up into the fender as far as the stock ones do, since the 52's should never be pushed into a reverse arch like the fronts are stock?