Sorry if you had trouble understanding my original question when I asked "Any suggestions on what to try". I talked to the guy at Transmission depot who assured me the tranny would work fine in the Grand National, are you telling me those guys running TH-400's have the wrong tranny's and their cars won't run either???? I didn't start the post to get criticized, if you can't help then don't contribute.......
I agree,
You asked for help. It was given and continues to be so, but some of the resident "experts" can do nothing better than kick you while you're down.
It was already stated that you would have been wise to go to a reputable builder, reiterating the same theme seems pretty childish to me.
Maybe they have no real TECH info to offer.