1961 and older was a cast iron torqueflight or a powerflite 2 speed depending on the car.
1962 was the first aluminum 727 with a 6 bolt crank and a flexplate.

The 1961 and older crank has 8 holes and the flange sticks out much further.

In the 59 dodge, the generator mounts on the exhaust manifold
and water pump housing. There are no bolt holes in the ends of the heads.
The power steering pump mounts to the water pump housing.
So other than the crankshaft and water pump housing you could use the rest of the 68 383.

Last year of a 361 in a car was 1966
Last year of a 413 in a car was 1965