...words have meaning........
Your 277 is of the 'A' engine family (277,301,303, 313, 318, 326), called the 'Poly', and used from 1956 through 1966, in Plymouth, Dodge and Dodge Trucks. Chrysler and DeSoto did not use the A engine. There are significant differences with the bellhousing bolt pattern and the crankshaft for the 1962 model year so engine swaps must bear this in mind.
As mentioned, replacement parts are readily available with the exception of particular pieces like the pistons. If you determine that the list of needed engine parts is getting expensive then consider shopping for another engine and, perhaps, a post-62 engine would be worth the extra labour..... Craigslist is your friend.
Also as mentioned, since you have the v-8 already it would be easier to keep it instead of gathering the needed parts to install an L6.