Head gasket is same across the range. It'll be Cortina Mk3 or Capri , I'm not sure if Transit were using them in low compression form back then, I don't think so. Haynes manual will work just fine for rebuilding a normal Pinto. If you want to look at tuning stuff then David Vizards is still the standard reference book.
Look at the cambelt cover to see what number is stamped in there to tell you if it's a 2.0 or 1.6.