ok i am going to attempt to replace the whole frame rails. i would appreciate any and all advice on the proper way to do this.do i need to brace the car, do i need to also replace other panels, etc. Thanks again guys!!

have a pro shop do it

I've been doing bodywork for over 20yrs. and there are a lot of veriables that go into doing this. Is the rest of the car all together? (welded) That helps if rails are all your doing. But it can still be dicy. Remember your rear suspention depends on all of that being precise (hight,length width and square) Not to mention the body lines if its not right

I don't know how capable you are, only you can answer that question.
Once you get everything out of the car (gas tank, rear end and suspension) you will see what you're up against. For the sake of neatness, you might want to consider replacing what the frame is welded to, namely, the floor. There are other gussetting members that you may or may not want to replace once you get into it.
This is not a project for the faint of heart or someone in a hurry. Measure everything 4 times and then measure it again to be SURE everything is lined up perfectly.
One more thing: You MUST have a good wire feed welder for this purpose and know how to use it. Oxy/Acet won't get it done.

When my rear frame rails were replaced, the aftermarket "almost full length" type were used. They're in a lot of catalogs. They begin just about at the 1 o'clock position if yer looking straight at the wheelwell. The entire trunk floor was replaced at the same time.
The guys that did it used the rearend/springs as a guide. I don't know if this was the best way but this is what they did:
They set the rearend with the springs/mounts attached up under the car and held it in place so that the springs were in their original, proper mounting points. They got the replacement rails in place, with the shackles attached to them also, and tacked them in place. Then the floor went in. They got it right the first time!

Good... bad...? I guess it helps to keep the original front third on the car if they're not too full of cancer.