I have a used PTC 9.5" converter to fit turbo 400. This converter uses a steel TH04 configuration stator and will net 3000 rpm highway cruise rpm, 3000 rpm @ 0 psi boost on a 231 iron headed motor. This will flash to 4500 on the T brake no probem and i have seen 4000 rpm on the foot brake. $500 shipped. I had to remove it since i did not like it slipping on the highway with the gearvendors. If you have a normal th400 and like to cruise at 3000 rpm it would work fine.