I agree that using wheels with proper backspacing and/or offset is the best method, BUT, not all of us can afford to have a set of custom wheels made. As TooMany mentioned, I think the adaptors are the way to go if you are exceeding 1/2" or so. I used a set of 1.5" adaptors on the back of mine to space out the 17" late model, 5 on 5" Jeep rims I am using on my 53 with a 1978 1/2 ton Chevy 12 bolt truck rear end.

Kevin
http://community.webshots.com/user/49chevyman?vhost=community
"The only people who do not make mistakes, are people who do not do anything."