NOT a Ford guy but!!!!

F10 = F100
A= 240 Six Cylinder
C= Built in Ontario Canada
D19955 Built in April 1968

Any Ford Windsor (260, 289, 302, 351w) or Cleavland (351c) will bolt up motor mount and bell housingwise to a 240 or 300 six cylinder. The trans was likely a t-18 truck 4 speed or the 3 speed version of a top loader. You can swap pretty much anything into it with the correct frame mounts for FE (360, 390, 427, 428) and 385 (429 and 460) will bolt in too, with the proper transmissions bell. The frames for I think 1964 to 1979 were the same. If you want, the disc brakes and power steering from a newer 70's truck will bolt on.