Originally Posted by stratostix

I removed the gas tank today gave it a closer inspection. Looks like the both trunk drop offs, rear frame rails and rear crossmember (not the tail light panel) will have to be replaced. I'm going to wire wheel all the metal back there (besides the obviously rotted area) to see how far I will have to cut the frame rails. Again, i will need your collective knowledge as this project progresses. I've NEVER worked on unibodies. Only wranglers (Tub on top of frame). I will be putting her up on jack stands tomorrow if time allows, remove the wheels and inspect the inner wheel wells. I will post more pics as I go. Please feel free to jump in and give me tips + advice. Thanks!

Originally Posted by jlg2002

Try to keep the repair on the aft side of the wheel wells and it will go very easy and relatively inexpensive est ($250). (just a butt joint repair on old frame to new frame and new inner qtr panels)

The other alternative is replacement of the entire frame rail and last time I looked they were about $300 each rail and are considerably more work to replace since the tie the floor pan into the rear of the car.

Originally Posted by jlg2002

Also used in aerospace it means the "after" or rear part of a vehicle or vessel. sorry for the confusion.
http://dictionary.infoplease.com/after

As far as a butt joint vs a lap joint- i don't think it really matters since the final product is a connection of the floor panels which help reinforce. From a construction perspective, the butt joint is easier IMO. There is a mustangs monthly tech article that shows how to do this:
http://www.mustangmonthly.com/projec...t/viewall.html