4.5/6.25 ECE drop.
Front: 2.5" drop spindle, 2" drop spring.
Rear: 6" drop spring, 1/4" spacer.
275/60/15 all around. Some rubbing in the front over bumps, so I recommend a slightly more narrow tire up front.
Install thread:
http://67-72chevytrucks.com/vboard/s...d.php?t=612794