I re-read my post, and can see how it maybe confused some people, Hell, it confused me! LOL.
I thought the poster was asking if a 383 would bolt to the existing 318 transmission in his car. Instead of whether this transmission would bolt to a 383 he was contemplating putting into his car. Sorry for the confusion.
Yes, this transmission from a 1964 Chrysler will bolt to a 383. Same Big Block engine family. Reuse the cables from the transmission in your car, rather than the cables with the Chrysler transmission.
To me, a motor mount is a 2-piece assembly; the steel engine bracket, plus the rubber isolater. To install a 383 in a car that a 318 came out of, you can reuse the 318 isolaters, but you will need to source 1962-1965 Big Block steel engine brackets. Bolt them together, and you have the proper engine mounts.
On early B-bodies, cars that had a 318 had the lower rad hose fitting on the passenger side of the radiator. Big Block cars had this fitting on the driver side. To make the engine installation easier without screwing around with your radiator, find a late '70's water pump housing that has the pump outlet on the passenger side. As a bonus, this also gives you more room around the oil filter. I hope this helps, and removes any confusion from my prior post.