Probably the best thing to do is get a complete vehicle that has a 6.5 chevy diesel turbo in it. Don't go with a naturally aspirated diesel, you WON'T be happy. As far as the transmission goes, you'll need the torque convertor at least (diesels have a way of blowing up gas convertors). There is a website for hopping up 6.2/6.5 diesels, it's part of the turbodiesel register: http://www.turbodieselregister.com/