I need you to come and inspect it. One of the only real fears I have for something like this is the 455 and the fuel economy in a world of high gas price as it makes longer distance touring expensive. I no longer have a close contact in the lower mainland so it is a big commitment to go have a look in person.
I posted it on a GMC forum to see if anyone is familiar with it or the owners.
Running right, they should get about 9 miles per US gallon, so about 26 L/100km, about on par with towing a trailer.
It's finally warm enough here I can work on Roxie, now that I have maintenance on the daily drivers out of the way.