67 and earlier converter is different from 68+ so having them build (or rebuild) your converter is the way to go in that you won't run into compatibility problems. mainly the crank register/snout of is the point of difference. but hughes knows what's up so you're in good hands.
Thanks for the heads up. When I last talked to Kevin at Hughes, he mentioned the differences. So it is something I will keep in mind when I get to that point.