Posted 23 June 2016 - 09:45 PM
I've done both repairs from firewall and from behind the sway bar mounts.
When doing a front section it need to be a joggled flange,. With a small lap Weld and some plugs. It's not my preferred repair but when you have a sound rest of rail it's by far a better option. As long as you pay close attention to detail, straightness etc all good. Be sure to check the length of the rail from a good front end, as if you are too short or too long it throws out your rad support but down low.
If doing the whole rail and or inner skirt you can run into many other alignment concerns, although if you prepare and have the balls to potentially do a Guido repair... And potentially bin your car....
I made a chassis jig with complete alignment capability which datums of the sills and the fsm's datum. All in all ye I spent 20 hours + building the jig alone let alone doing the rail, skirt, tower, rad supt etc etc.
Rail height is one main concern, but other factors to consider is strut tower to rail, height & width as well as along its length.
I don't recommend it to those trying it for the first time, without serious help or experience from someone in the game.
Just a suggestion.
I have lots of pics of both types of repairs.