I had heard that HDH was buying DC4's to remove the engines from for our Caribou's.
Plenty of C54 and DC4 aircraft around that time. I believe that they were all zero timed before fitting.
When you consider the engines must be seventy years old they have served well, but of course they are one of the major weakness's now.
Only air acraft I ever heard that sounded better, was the NA AJ2P Savages from the USN that stage through Australia to do an aerial survey of New Zealand.
Double row wasps with the tube really great sound
Regards
Col