The 6.5 motor mounts will fit a 454, so doubtful they will fit small block. The transmission should bolt up, but you will need a torque converter for a gasser. I know you read this on your other thread, but it will be cheaper to buy a gasser with bad engine and swap it in it. Welcome to the site by the way and not trying to discourage anybody and a project. Just on the time factor alone would make me get a truck designed for your 350. Then there is the money thing.