Don't forget to check the bushings. You can find reasonable bushing driver sets on ebay. Check out What It Takes Transmission's web site for a good schematic. They also sell oddball parts for decent prices. Here are my 904 build specs:

73 904 complete
4.2 billet front band lever (Cope Racing)
Cope Racing heavy duty band strut 
Cope Racing rear billet servo
New sprag inner race, springs and rollers
Cope Racing Front semi-rigid band red lining
Cope Racing Low reverse band red lining
Teflon pump support rings
Unrestricted pump support oil feed
Blocked front pump vent and relocated vent to upper tail shaft
Drilled front clutch retainer for quick piston release
Blocked accumulator - .002" clearance between piston and valve body
Front clutch:  5 - .061" Alto Red frictions, 5 - .068" Kolene steels.  Clearance = .060"
Rear clutch: 4 -.061" Alto Red frictions, 5 - .068" Kolene steels.  Clearance = .036"
Cope Racing 4 pin Low gear front planetary 2.74 first gear, 1.54 second gear (factory steel 4 planetary from Cope Racing).  Replaced thrust washer
Replaced all bushings
Used original rear planetary thrust washer
Replaced front clutch return spring with Cope Racing multi-spring clutch retainer
Total end play .013"
Gear train end play .009"
Front band adjustment - tighten to 70 inch pounds, back off 2 turns
Rear band adjustment - tighten to 70 inch pounds, back off 2 turns
Output shaft support bolts - 150 inch pounds
Pump body bolt torque - 160 inch lbs
Front servo pivot rod plug - 150 inch lbs
Tail housing bolts - 24 foot lbs
Pump to case bolts - 175 inch lbs
CSR transmission shield
ATI transmission pan - bolts 150 inch lbs
A&A Trans Brake - bolts 70 inch lbs (per A&A)
Air tested front, rear clutches, front and rear servos using 30psi.

Good luck with your build.