Agreed. It currently has a real old turbo action converter in there which I think might be going away. So really looking to just try something, but may end up going new.
Was not aware of different splines for a 904 or pilot, so good questions.
The pilot and splines, depend on the year of the engine/crank, and the year of the 904. I have several different converters for the 904.
small pilot small spline
small pilot big spline
big pilot big spline
The reason I say to contact a mfg is stock is "super competitive" and the weight of the car, rear ratio, 1st gear ratio, engine torque can all make a huge difference in the converter. I have a couple of different engines, and everything else being the same except the engine, the converter has a 800 rpm difference in stall speed.
Better stop this now. the mods don't like this stuff in a for sale or wanted post. If you need contact me in a convo.