Are those tubeless rims? If not,they look like Firestone "Widow-Makers"! you may get lucky,and find a '58/'59 bus,with a good front clip. To re-build your brakes,with new lines/hoses,will cost in the $1,000.00 range. If you "run" 900X20'00's,you'll achieve 55 M.P.H.,without over-taxing your engine. Just make sure to eliminate the "Widow-Makers". Billy W's'59 Viking bus came with the 10-bolt,5-hole,(3-piece) rims. NICE front clip,too.
http://s1181.photobucket.com/user/willybickey/media/MOV00201.mp4.html?sort=6&o=24 Hope this helps.
