I build my own 904 for bracket racing..I use stock discs and steels....A stock rebuilt kit will would just fine...get everything cleaned...check your clearance on your clutch pacs...
They are so simple the guy post above mine could do...
Transtar Super Deluxe Overhaul Kit for Chrysler TF6 (A904) 60-Up from Northern Auto Parts
I have a great video that walks you thru the rebuilding of a 727...and the 904 is very similar in design....It is free...just send me your email address and I will send you a link for the download...it is 4.7 gb so dont have dial up...