TRANS delahmaz --haveing a 904 built up and 391 gears , was looking 4 a lower HIway RPM , with keeping the lowgear launch capabilitys ? VIOLA!!! my search found these features with NO floor cutz & mates to original 904 trans = GEAR VENDOR 2 the rescue? - bolt-on overdrive unit 4 about the same cost of 700R4- - check their website - for full info -- seems their bolt on units fit both ( 727 & 904) and gives these parameters -adding more gears once installed ?? can anyone comment with first hand knowledge - on these GEAR VENDOR UNITS ?? Cudanutz