Is there any difference in the pressed steel running board braces from year to year or from front to back? I have a frame that I went to put braces on and the holes don't line up. They are about 3/8 to 1/2 inch farther apart on the braces and I don't know if there is any difference in brackets or if I need to stretch the frame farther apart.
Measure your frame,center to center on the holes should be 21 1/2 inches. If your RB brackets are bent it will be off from that.
The '26/'27 style running board is slightly wider than the '20 to '25 style. As a result of this, the later running board brackets extend out a bit more than the earlier ones do. I don't recall the amount, and don't have any to measure. But it is about or slightly more than 1/2 inch on each side. As far as the measurements where the brackets are attached to the frame? Nearly twenty million of them (off the top of my head) are all alike.
From what I recall in a thread a few years ago, there were also late replacement brackets that were the longer size, and had two holes near the end. The single inner hole fit both early and late running boards. The channel reached far enough out for the late running boards which used the outermost of the two outer holes. If used to replace the bracket on an earlier car, the innermost of the two outer holes was used. It was up to the repairman whether to cut that half inch off the channel or not.
I am fairly sure that most, if not all, the factory installed onto '26/'27 style frames had only the one outer hole to fit the late running boards. But I have seen a few brackets with the double outer holes.
In short, I think there are three variations of the "pressed channel" model T running board brackets (not including TT).
1, The '20 to '25 early style for the narrower earlier running boards.
2, The slightly wider brackets for '26/'27.
3, The later replacements made wider to fit the later running boards, but drilled to fit both wider and narrower running boards.
All of them fit the frame exactly alike. How Jack D says.
A secondary measurement is that the outside to outside of the frame rail channels is almost exactly 23 inches. Otherwise your frame is bent.
Drive carefully, and have a Happy New Year! W2