Frame Measurements

[SPG]

I just want clarification on two sources I found for measurements as I don't want to make any mistakes

On our site we have this page for 73 and 80
https://nastyz28.com/tech/framechk.html
but I have this picture where some of the measurements are slightly different for a 1976 (I have a 75)

From what I know about these cars, the 80 measurements should be the same but I have conflicting info so I just want to be sure before I jot down the wrong info

 

[Camaro Tim01]

I ran into the same problem, I have a 76 and I measured from the center to center of the top rear shackle bolts, fortunately I got the 47 1/8" as my rails were original and mint... I then matched up that measure to the diagram that had it and went with that one for the rest of the measurements.
I think it was the diagram in the assembly manual, which I believe is the pic you have posted

 

[Camaro Tim01]

If you think about it....
If you measure between the rails and the 37" measurement and the height difference from the floor to the frame where the shock goes and the height from floor to rear rail ( like in the diagrams ) If those match up, your frame hasnt moved and your good to go... there's no way the frame rail wouldnt move up or down or sideways if something else was off or bent, if they match up, the rear is correct

 

[SPG]

I measured the car with what I have printed and looks to be square
I can't do the floor measurements (easily) because the car is currently sideways, but I'm pretty confident my car is fine
This also means I'm not going to spend the extra 3k on a new subframe from chassisworks

 

[Camaro Tim01]

from the floor up are just hypothetical measures unless you sit the car the way they have the diagram and thats almost impossible.
What you want is simply the difference between measures to see if your OK
for example if you look at the rear frame you see the following :
X=6 , B-19 , 17 1/8 (I think its 1/8)
What you want to know is simply if the differences are the same...
there should be a 13" difference between x=6 point and b-19, 11 1/8" difference between x=6 and 17 1/8 point, and a 1 7/8" difference between b-19 and 17 1/8 points