Keith,
I had the radiator in our Silversides re-cored in Ft. Lauderdale, Florida in an off the way radiator shop, but the guy really knew what he was doing. He used a new core that was 5" thick. The recore price was a little over $800 (that was 9 years ago.) The frame that holds in the core is part of the tank and core holder as well and that had been broken, so I had a shop weld the aluminum back together and they magnafluxed it to be sure there were no leaks, that was an additional $300. I got a high volume fan from a rebuilder (used) and that was $100. I didn't have the original bracket that holds the fan on a remote offset pulley and couldn't find one anywhere here in Florida so I built one out of 5/8" plate steel (cutit with a plasma cutter and ground the sides smooth.) I added a brace but I still get a little vibration between 1950-to- 2000 rpm, then it goes away.
Good luck,
Dave Siegel 1948 Silversides
Naples, Florida