Hey guys, I've got a '74 F100 with a 300 straight 6. I'm putting the 3" lowering dream beams in it. I'm going to replace the springs as well. The springs for the six are different than the ones for the 302/351/390 even thou the six weighs as much or more than the 302. I may go to a 302 someday but for now I'm staying with the six. Any info on why the springs are different?