Huggy,
Welcome and congrats on having one of the best V8's on the planet!
Your flathead is a '52 or '53 Merc according to the heads, but as all Ford/Merc flathead V8 stuff interchanges you won't know for sure until you dig deeper into the engine.

For the sake of argument the EAC would have the 4" stroke crank and HP was rated at 110. None of the other casting numbers mean anything at present - apparently local foundry ids.

Did they change the entire engine or just the block/heads? i.e. - does your carburator mount with 3 bolts (Ford intake) or 4 bolts (Merc intake)? You should be able to find on the rear passenger corner of the intake flat an alpha-numeric series stamped there that will tell you when your engine was assembled.

Tranny: I don't have any number refs close at hand, but you should have one of 3 that Ford used in '49.
Standard equip - Light duty 3 spd, all synchro (looks like car tranny - narrow gear box.
Optional equip - Heavy duty 3 spd, synchro 2/3 spur 1/R much larger case. OR a 4 spd, all spur gears.