on the 440 use a 1969 to 1974 block, these have the higher alloy content and have an extra strengthing rib running down the side. try to find a good block with .525 thick main webbing around the shell. most 440s have .375 . hope this helps.
You don't need any kind of swap mounts, thats money wasted, take the mounts off of the 318 and they will bolt right up to the big block, both big block and small block have the same bosses on the block, put the engine right in, get b-body headers and go driving. My brother has a 64 plymouth savoy, had a wide block 318 we installed a 426 hemi, right back in the same location, same k-frame as your car.
In '71 after I got home from the Army, we stuffed a 440 Mag into my '64 Belvedere that had the old poly head 318. I can't remember exactly what we did for mounts though......With 2.73 rear screws she would get waaaaay up there over 135 ! And on bias ply tires....I have NO idea why I am still alive....... :shock: :shock: :shock: :shock: :shock: :shock: