904 transmission questions

What parts do I need to rebuild a 904 to handle the torque and horse power that my 408 will produce?  

If you find an A-999, pretty much nuthin. THe thing about the A-999 that I don't particularly care for are the lower first and second planetaries. They make first and second gears a lower ratio in order to get the later vehicles with a lot of weight and super high rear gears to accelerate quicker. So, from second gear to third, it's a long jump between ratios. That's just not needed in a hot street or race application, so I just get the 5 disc front drum and wide bands used in the A-999 and upgrade the A-904. There are plenty of companies that offer mucho expensive parts for the 904/727, but you can make the A-904 live without that stuff unless you're doin something like a blower or some nitrous. Of course, I'd get a good rebuild kit with the kevlar bands, and a good shift kit. Trans-Go makes the best I've seen for the Torqueflites. The Torqueflite ain't like all these other transmissions. All the rest, you have to add stuff to make um shift hard. The Torqueflights had stuff added to make them shift soft. LOL The good kits are the ones that come with the accumulator block rod. They completely eliminate the accumulator spring and replace it with a rod that holds it firmly in place, rendering it useless. This helps firm up the shifts. There's also an oil restrictor that you drive into one of the valve body passages in the transmission case. I always just tap that passage opening to 1/4" NPT, drill an 1/8" hole into a flush pipe plug and screw it into there instead of using the restrictor. More permanent that way and does the same thing. This restriction stops the high gear band from trying to engage going into second gear. This is an inherant design flaw in the Torqueflites and gives the sensation of a hard second gear shift, when in reality, what's happening is second AND third gear are trying to engage at the same time, and it results in a BANG going into second. The restrictor eliminates this and actually does help firm up the second and third gear shifts. Lots of other little stuff that a GOOD kit covers, too. There's nuthin to a Torqueflite, really. Just take pictures the first time you remove the valve body so the placement of the check balls doesn't overwhelm you. Oh...you leave one or two of those out, too. LMAO. EDIT: I forgot to mention one very important part. The 5.0 to 1 ratio front band lever. This speeds up front band actuation significantly and firms up shifts as well. The stock ones are usually in the 2.0-3.0 range.  
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Here's a nice article on the A-904.  

http://www.moparmusclemagazine.com/howto/5123_904_three_speed_automatic_transmission_build/index.html


The 5 disc drum is mentioned, but not dwelled upon. I just now got a 5 disc direct drum today for mine.

Another good article here as well.

http://www.allpar.com/mopar/transmissions/torqueflite-tom-hand.html  
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It is enough that Jesus died and that he died for me.

Also another great article here.

http://www.carcraft.com/techfaq/116_0701_tci_transmission/index.html

You can clearly see the size differences between the 904 and 727 pieces. It is very clear that the 727 will take much more power to drive than the 904. Also of course, is the other side of the spectrum. Since the 727 is bigger, it will handle more power, BUT as long as you plan on having 500 or less horse power in a small block, the 904 will live just fine, as long as a few simple mods are done. To me, the trade off for more power at the rear wheels is a no brainer. I would imagine that although we want to spout our street cars are all powerful, only a handful really, honestly make 500 or more horse power. Hope this helps.  
____________________

It is enough that Jesus died and that he died for me.