Not sure what rear springs i have.1977 k20 D44/12 bolt. i am putting a 14bolt ff and 8lug outters on front. How do i measure rear springs? What driveline corrections are needed, if any, with the six inch lift and how do i determine if there is a problem? Also, what shocks would you recommend? The components i bought are: rear shackle flip, rear bushing kit, front greasable shackles, front greasable main eye kit, sway bar bushing kit, 4.5 inch bump stops, 6 inch spring kit for use with shackle flip. I still need to buy steering brace, 1 inch body lift with body mounts, sway bar disconnect, brake lines, 14 bolt disc kit with lines. Any help or recommendations anyone might have would be greatly appreciated. Thanks.