If it still has the clutch attached it should be 7.5in dia from memory, also at the rear of the block from the two top belhousing bolts to the deck height it should be 1.1in for 1600, just under 1in for 1500 and level with the belhousing sandwich plate for 1100/1300 . Err the block of EGR/ emissions attached to the intake say that it could be most likely be a 1600 from 1977 when emissions got tougher. Earlier 1600 and 1300 didn't have that block of EGR stuff, some 1600 Escort mk2 came out with double barrel carb (gt1600 Capri type)
The engine number is on the exh side front top and should start with CK---- if I am correct ...I haven't mucked about with Kent motors for ages for obvious reasons
Edit... Kent motors started back in 1959 for the Anglia 105e and were pre x/f until the UK escort came on the scene 1967/8 (1969 for Aust) . Sorry the huge info hit lol.