Find a pair (or three) of 1971 to ~1991 4x4 Blazer/K10 wheels. They are 6 lug, 15", with a 6" wide version (I have read 6.5") and an 8" wide version, and are made to clear the disc brakes that CPP's kit copies. They can be identified by having 4 hubcap nubs instead of 3, and do not have the bumps in between the lugnut holes. Otherwise they look the same as a 60s C10 wheel if you don't look too closely. I am running a pair of 6" wide (6.5"?) wheels on my '50 with the CPP disc kit, and have a third one mounted as a spare.
Maye this image link borrowed from another forum will work...
http://67-72chevytrucks.com/vboard/attachment.php?attachmentid=1109003&stc=1&d=1368956044
