Tom
there are a number of books about engine swapping and there are lots of street- and hot-rodding web sites that can step you thru the process.
The thing is (as EZ said) you have to
fabricate what you need. If you had a Furd or Chebby of that era, its available in catalogs; for a LaSalle, not so much.
Again, many of those catalog parts could be
adapted for your car, but are not a bolt-in.
You have to think about systems : fuel, exhaust, carb linkage, trans shifter, cooling -engine- trans, drive train mounts and alignment, spring and shock calibration, and electrical.........to name a few.
Its not rocket surgery

, but it is time consuming and you have to be willing to work out each solution.
Take a look at
http://www.hotrodders.com/forum/http://www.streetrodding.com/Let us know what you're thinking, we're here to help.
Gary