Rear deep lip on first gen F-body (???)

[LSfan70s]

I've been searching a lot but with no succes. So feel free to answer my question with links (PM me if need) or hit me with key words to help me find what I'm looking for.
What I need is the specific: parts, measurements, brands, work to do, or whatever I need to get 18"x12" with a nice deep lip in the back of my 68 F-body (Firebird for what you can see in my sig)
Where I live there are no experts or people that has done this before, but there are very good experienced welders and body shops that can do anything.
Basicly, I guess what I need to know is the housing length I need, how high and wide I must mofidy the wheel wels, do I need to modify the rear chassis to get 12" wide wheels?
I know there are plany of people that has done this before, but how? Or who should I call? Or what magic measurement tool should I buy that will let me know all this info.

Thanks guys.

[907rs]

Most everyone uses the Detroit Speed and Engineering mini tub kit. Do a search for mini tub and you'll find tons of info. You can also check out DSE's website for tons of pics (Link to the left)

There is no magic number for the rear end width, the tolerances back when these cars were built varied greatly from car to car. It'd be best to complete the mini tub, purchase the wheels and tires, (most people run 6" back-spacing with a 335/30/18) then mock them up square in the wheel wells to get a good measurement for rear end width.

Good luck. There are plenty of people here that have completed the install to answer questions.