904 sittin for a decade?

call the boys at TCS in Langley they do all the goodies for 904s I got my rebuild stuff from them it cost more for us Canadians than the american guys are quoting you but it was around 900 for the full race rebuild kit , the 24 spring return module and the billet steel drum kit that includes the aluminum piston that is designed to work with the return module , and I also got the new pump kit but you rarely need to replace them so that was a waste of about 35 bucks on my part . Add in a good 10" converter and a valve body and your looking at another 6-700 hundred bucks on top of the 900 to "do it right ", they run a 1400 hp pro car with this setup so I doubt you'll ever break it

PS I used the youtube videos to do mine between the series for the 904 and the one for the 727 you'll learn alot