I found a kit for a 55-59 3600 from ebay. i had to drill out the top 2 holes from 7/16 to 1/2. then took the flapper wheel on my grinder to the bracket where it just touching a small bit. the calipers on this kit came from a 86 k20 and the rotors are from a 91 suburban. bad part is the stock wheel touches the calipers. but i was replacing them anyway the had a ring around the mounting edge. i also tried a newer 8 lug rim about 2008 these rims put most of the tire in and these hit the tie rods. im thinking spacer but i will have to change the studs out because they will be to short.