Chryco, what exactly does "properly built with good parts of course" mean? I'm asking 'cause I'd like help. I am replacing my 318 with a balanced 340 and want to keep my 904 because many guys say it frees more horsepower than a 727. I was going to buy a heavy duty rebuild kit for the 904, along with a new valve body, torque converter, kickdown lever, deeper tranny pan and I think that's it. And I'd have a proffessional transmission shop do the work. Would that be enough to handle my new power?