Firstly, don't buy Edelbrock heads. Although I haven't used them myself, I haven't heard anything to lead me to believe that spending the extra cash on those heads warrants any performance improvements they may have. Also, the horsepower of your engine doesn't matter so much when it comes to what transmission to use, it's the torque. Any 455 is a torque MONSTER, and it will turn a t-350 into little pieces of shrapnel in no time. You absolutely have to find a turbo 400 if you plan on using a 455.
Also...go to a local boneyard and buy some big gnarly engine mounts. You'll need them if the engine doesn't come with any
