Trailing arm length, C-Notch Placement

[Bartonius]

What is the length of our trailing arms center of bushing to center of axle?
I am looking at a set of surplus NASCAR trailing arms that are 51" C to C, i tried to measure my junk ones and they seem just about 51" just looking for confirmation.

Also, when adding C-notches to the frame should the center of the notch opening be centered on the center of the bump stop bracket location? I have my truck down to the frame and forgot to measure, actually I forgot to measure most things.

Thanks in advance,