I have an 85 w150 with the 360 and granny four speed. I have been told i can lift it 4 inches without extending drive shafts but i am not sure. I have about an inch and a quarter of splines showing on both my shafts now. I am getting a parts truck and i wanted to stack some of those leaf springs onto mine to get a little bit of lift and stiffen up the suspension a little bit. I have 4 on the front and 6 on the back. I am wanting to add two or three leafs to the front and back but im not sure how much that will lift me and i dont know if i will b able to do it without any drive shaft problems.