Rear frame rail narrowing for B-body

[Devildog]

Anyone have the rear frame rails narrowed and wheels tubbed for larger wheels on a b-body? I was wondering if someone could explain the process and if I should use the existing frame rails or a kit? i'm looking to widen the wheel wells to fit 24" wide slicks in the rear. Pics of someone else's car and an explanation of where and how to relocate the frame rails would be a big help.

Thanks.