71 K10 frame questions

[C3pilot]

So the 71 swb k10 project that I picked up is down to frame and axles. I sent it to a body shop that has a frame machine and they assured me that they could get the numbers for a ‘71 k10...well we all know how the story goes from there. There unable to get numbers to measure the frame but say it’s over 4 inches out? How they came up with that number, I don’t know.

I’ve found the PDFs here on the sight that have the numbers for c10 frames but not k10s.

My question is; how much does the frame rail “narrow” at the engine? Or is the frame straight rail straight from front to back?

Here’s a few pics of the frame. Frame horns are bent, but is the frame 4 inches out? We think it took a right front impact of some kind. I’d consider a donor frame but had a hard time finding this one and it has a clean title so I’d like to try to have it repaired.

Any suggestions or pics of a frame that I can compare mine to.

Thx
C3pilot