Hello Again, Long ago in my camaros history it was hit on the pasenger side rear quarter. well along with the rusted trunk the frame rails were bent and rusted out I am replacing the with 45' extensions my question is the one frame rail is good and straight does any know or could you measure how far apart from inside one to inside another to each frame rails I can get them line up and all I just want to make sure they are the correct distance apart sych as parrallel.. etc.. Thank you everyone whom can help me out

Get all the parts together that you will need to finish the project and trial assemble the car before you weld anything up. I'm speaking of the frame rail, floor, tail panel, bumper, etc.
I'm sure you can find another car to measure to get an estimate, but if you can find two, I wouldn't be surprised if the measurements were as much as 1/4" - 1/2" different.
Trial fit your car, just to be sure.

Thanks for the reply, does anyone out there working on theres have the time to possibly give me an estimated spacing size. I would really appreciate it I hope to start putting some of this stuff back together this weekend. Thank you

according to the body by fisher manual
"42-7/8 ------ Inboard edge of side rail at centerline of shackle bolt hole"
And you can pull a diagonal measurement from the front spring perch, there is a master guage hole there from the guage hole to the rear shackle bolt hole (centerline) should measure 66-11/16 IE: (going from driverside front spring perch gauge hole to passanger side inboard rear shackle bolt hole center) If i get my scanner working i'll email you a pic. hope this helps