I have a KLAM retarder, orignally in a Mustang Emissions Chassis dyno here in PA. I "found it" in a local automotive junkyard and struck a deal, I got the retarder and all the sensors, no computer or power supply. I contacted Mustang for info and they would not supply any so I contacted the manufacturer in Spain and they were more than happy to help me figureout how to use this thing.
It is rated for 280lb ft at 7000rpms using 40 amps (off the top of my head without looking up my notes) and can take bursts up to 8000rpms. I'm only using 10amps right now and it is only setup to run my small engines. I'm currently looking at building some rollers to hook up to this retarder so I can test a complete tractor (see other post on the forum on this project). The retarder would hook up to the end of the rollers or I can use it as an engine dyno. But like usual to many projects and not enough $$$'s . . . then again building the "toys" is half the fun!