As far as fitting a 348 in the engine bay, I have a 348 3x2 that I want to put in my '64 but measuring indicates that the firewall MAY need to be massaged to clear the valve covers, not sure. The general DID put the "W" head engines in the >2ton trucks but the cab sits quite a bit higher off the frame which allows the necessary firewall clearance. As far as facts on the engine itself, this is a good place to get the straight goods http://www.348-409.com/