49 frame width

[b-mac]

I'm looking for the frame with of a '49, 3100, at the Front and Middle running board mounts.
I'm in the middle of an s10 swap. Original frame is long gone... Current circumstance in my garage make installing the bed before mounting the running boards somewhat problematic.

So my thought was, if I knew the width of the original frame, and the width of the S10 frame, at those mounting points, I could calculate the exact amount needed to trim off the original running board mounts...or what dimension the new ones need to me.

I can't exactly follow Chris' "How To" because I had to fab my own floor (was gone when I got the cab) and therefore, my own mounts. Cab is also sitting lower than Chris'.

Found diagrams for S10 frame dimensions, and the 1949 Pickup manual, but I can't seem to find the edge to edge frame dimension.

Any help is appreciated.

TLDR: need 49 frame width to fab S10 running board mounts