Just thought that there may be inherent weakness in the early trans. I know that Ma Mopar used them in the slant 6 and 273 powered "B" bodies in '65, but went to a 727 in the same "B" body with a 318.
a trans is a trans,,,just because it is shifted my cable doesnt meen it wont hold up,,,its all in how it was built,,,ive seen 904 trannys in big B bodies hold up in class racing if built properly