I think that removing the engine with the three speed connected is not a problem but the 4-speed does not come over the clutch-housing cross member (the rear motor mount cross-member).
There is no transmission cross-member (nor rear mount on the manual transmissions) in 1954.
I would not recommend taking the cab off to get the engine and transmission off UNLESS you are doing a frame-off restoration. In that case, I have even lifted a 54 engine and hydra-matic transmission together off the chassis.
I usually either remove the transmissions first and then the engine; or, I unbolt the transmissions, leave them in place, and remove the engines.
Tim
