A friend of mine has a '03 2500HD that he is putting a D60 under the front of. The kit he is using has 9/16" bolts for the shackles and is supposed to use 73-87(91) front GM springs. The springs are BDS. Where can he buy 9/16" bushings for the rear eye of the front spring? When I searched I found posts saying that a 9/16" bolt isn't the best thing to use here, but the shackles are made for a 9/16" bolt. Are there any other options? How bad would it be to use a 9/16" bushing?