I had a virtually unused 500 and a Turbo 400 trans that was intended to be installed into my 59 Suburban. Unfortunately, some metal buzzards got into my storage area and carried it off, along with a few other engines. I assume they got sold for scrap iron! I've got a 1970 Fleetwood Brougham with a 472/400 powertrain that will probably get used for that project, but it's got about 250K miles on it! That one will need a full rebuild, engine and trans.
Jerry