This old wrench is 11 3/4 inches long. DOE 1 1/8 inches on one side 1 1/4 on the other.
The number would make it a McCormick/Deering Tractor Wrench, never seen the /M\ logo before...hmm
My guess is you have a Birdsell wrench(later bought by Allis Chalmers) Shown under both company names in Rathbone. Assume (M) is foundry mark as different mark is shown in Allis section.
Thanks for the help...it shows up on page eleven in P. T. Rathbone book under Allis Chalmers Co.