318 2 brl to 340 4 brl conversion Whats needed?

66, GMs are not Mopars (Thank GOD for that)... You MUST run a kickdown on a mopar. at all times. Unless you have a manual valve body (means no automatic features). It only take about 50 miles of mixed driving to completely destroy and otherwise good tranny with none. And, manually shifting a torqueflight is not good for it either. Get the right governor assembly, and the right kickdown, and it will be everything you want.