904 trans

Yup, 273, 318, 340, 360 can all use the same trans, but not exactly the same converter.
The converter is balanced different for a 318 than it is for a 360 for example.
I don't know for sure on your 340 or I would tell you, but a 318 is internally balanced and a 360 uses the harmonic balancer and converter or flywheel/flex plate to balance the engine. (external balance)
The 340 had different crank shafts (some internal balance and some external)
Unfortunately I don't know how to tell the difference without doing a google search or asking here. :D

The trans case itself bolts right up to all the above.