'Cuda Rear Frame Rail Replacement

[70HoosierCuda]

I need to replace both rear frame rails on my '70 'Cuda....unfortunately the trunk pan and floor pans also need replaced (along with nearly everything else ).
 Not sure the best way to go about doing the rails in this scenario...any advice, opinions, pictures would be appreciated.

Thanks in advance

[HP_Cuda]

This is painful but doable.

Basically the car needs to go on a frame rack and measurements taken. Compare those measurements to the factory specs and see if they are within spec. Sometimes when you start a project it starts from a different place then you expect. Meaning that sometimes your car was wrecked and fixed but the frame was not.

Anyway, are you planning on tackling this yourself?

[70HoosierCuda]

No signs of collision damage..just heavily rusted.
Yes I plan to do all the tasks myself as restoration work isn't new to me but the logistics of this has me somewhat baffled.
Unfortunately I don't have a frame table and would prefer not to farm out the work.

[anlauto]

Dynacorn sells a one piece rear section where the frame rails, trunk floor, center floor etc...is already assembled in one large piece. That's the way I would do it. You would need to convert the trunk floor from Challenger to Cuda, but other then that it would save you a tremendous amount of work 

[70HoosierCuda]

Dynacorn sells a one piece rear section where the frame rails, trunk floor, center floor etc...is already assembled in one large piece. That's the way I would do it. You would need to convert the trunk floor from Challenger to Cuda, but other then that it would save you a tremendous amount of work 

Thanks for the advice.
Found it online...p/n #6000WT...approximate price was $1500. 
Definitely something to consider. Is the only difference the trunk pan?

Looks like I'd still need a frame table regardless

[anlauto]

The only difference is the oval circle opening for the gas tank filler in the trunk floor.
I just bought one last week, shipped from California to NY for $1598.00 all in.

[72bluNblu]

How rusted is the floor and "everything else"?

I just replaced half of my right side rear rail and about 2/3 of my driver's rear rail, as well as the sections of trunk floor that were above them. I measured everything, removed one rail, replaced it, measured everything again, removed the other rail, replaced it, and measured to make sure I got it right. Then I replaced the trunk floor sections, having left them detached from the new rails when they were installed. But my shock crossmember and rear cross panel were intact, so I was able to leave those in place and weld the rails to them, which allowed me to leave most the trunk floor separate from the new rails.

If there's enough structure and floor left to support the car you can remove the rails one at a time and use the remaining floor to help line up the new rails. Once the rails are located you can get to replacing the trunk floor and anything else. I'm getting ready to do new quarters now that the rails are done.

[70HoosierCuda]

Thanks for the help so far, guys...keep it coming

72bluNblu: That's reassuring...I appreciate the input. I'll have to find time to really look over my floors, etc soon and see where I can go from there (it's been covered up in the garage since I got it home).
Any pictures you could share from your work?

[AARTA340]

We all know the Cuda has a shorter wheel base than the Challenger, so with that in mind, where is the difference in the two? Somewhere there has to be shorter floor pans or something. 

[roadman5312]

We all know the Cuda has a shorter wheel base than the Challenger, so with that in mind, where is the difference in the two? Somewhere there has to be shorter floor pans or something. 

                                                     

[anlauto]

Rear footwells

[70HoosierCuda]

We all know the Cuda has a shorter wheel base than the Challenger, so with that in mind, where is the difference in the two? Somewhere there has to be shorter floor pans or something. 

Rear footwells

So those would need to be swapped out as well as the trunk pan?

[anlauto]

So those would need to be swapped out as well as the trunk pan?

NO...those are not included in the WT6000 , neither are the trunk extensions which are different between Cuda and Challenger

[IMNCARN82]

The AMD rear frame rails are a perfect fit. Flawless.  And I never say that.  Best piece I've ever gotten. Worth every penny.  Lot's of work tho.    I put one side in on my cuda.    In general, AMD is by far the best repop. for anything IMO.

R/T

[72bluNblu]

Here's some pictures of my rail and trunk pan section replacements. Yes, I know, I'm not the greatest MIG welder in the world. But in my defense, a couple of my patches should have been bigger to get out into cleaner metal, and once again I was welding outside, as usual. Were this some kind of show car I probably would have needed to buy a full trunk pan, drop offs, and wheel tubs. But, it's not a show car, I'm not rich, and it seemed like a shame to replace whole panels when 90% of them were good. And thanks to the factory's liberal use of seam sealer, most of the ugly looking stuff gets covered, which is why I didn't grind it all flush. Some of the rust on my car is "typical", some is not. Some of it is very localized, having to do with the rodents that lived in it at some point in it's life using the factory internal bracing to makes homes, ie, stuffing old carpet into the compartmentalized sections of frame, which then rusted out in very specific segments, while the sections on either side were fine.

What I started with