/6 904 transmission swap still having problems....

Another possibility is that the shift selector linkage is not correctly adjusted. If it's revving high, that probably means it's not shifting out of second (or if it's revving really high, it's not shifting out of first). Perhaps when the shifter indicates "D", the transmission is actually in "2" or "1". That could also explain the lack of reverse; perhaps when the shifter indicates "R", the transmission is actually in "N".