I used a 1967 Chevy half ton in mine, was the right width and has the 6 lugs. just had to weld spring perches on. pretty easy swap.
here is a link to some others that might fit as well
http://www.chevytalk.org/fusionbb/printpost.php?tid/173541/

I also used the t-5 transmission swap that was much simpler than all the info out there would lead you to believe .

John