65 Cuda V8 #s...another question.

Rookie question (thanks for all the help on my last purchase of a 1965).

1965 Barracuda 273 (2 barrel, I think).

Went to look at another one today.
Sitting a while, but V8, Auto / and evan an A/C car again.

LOOKS like the original set-up...
~I know I cannot see the #s on the DRIVER'S SIDE OF THE BLOCK.
They must be behind the manifold.

~There's supposed to be a # and a date code cast into the FRONT of the block, right UNDER the Driver's head gasket, I thought.

Wiped, wire brushed, etc. ...saw nothing.
Wiped it down to the paint on the block, and down about 2" from the head gasket line...???
Q=Any hints? Pictures would be a HUGE help.

Looks orig. All the A/C parts are still intact, drier, everything.

Q=Couldn't see a casting # on the intake manifold to use that to determine the application.
Q=I do have the # from the Driver's exhaust manifold, though.

Q=But couldn't the engine be switched to a 318 or something, and the original manifolds be reused? If so, that wouldn't pin it down necessarily.

Thanks in advance.