I've had a 5.3L for about a year that I planned on running in my Third gen with a T56. I think I'm now leaning more toward dropping it into my '79 with an automatic. I haven't researched this at all since before I was planning on running a manual. What year 4l60e's am I looking for to be compatible with a Gen III motor and wiring? I'm not running a carb or anything. Will the older LT1 era transmissions work just as well as the ones that came with a Gen III motor?