The Stovebolt Site Forums The Parking Lot Tons 'o Fun Advice needed, GMC V6 engine

I have a '57 chevy 1-ton that I will be restoring as soon as I have time to work on it. It has a 235, 4 sp (SM420 I think)and 4.57 rear gears. I don't yet know if the engine is okay but it probably is. I also have a '66 GMC semi that was on my property when I bought it. It has a 478 V6. I've been contemplating the prospect of putting the V6 in the 3800. I don't have any idea if it will even fit. I've gotten some info from the 6066 GMC site about the engine and I'm thinking it needs to run at pretty low rpm's, maybe 1800 to 2000. Does anybody know if this engine will fit into a TF truck and connect to the SM420? What is a comfortable rpm for this engine to cruise at? Any other thoughts on the viabilty of this swap? Thanks in advance for any insight.