Jett and Nelson .40's? :huh: I'm not familiar with them, but I believe they are made in the USA for pylon racing... I've seen a Nelson water-cooled version (converted?) before in a rigger, the guy said it was big bucks. It looked different from the typical marine motors, sort of like an on-road novarossi 21 with the case fins, but bigger.
I see they both placed in Sport 40-1 at the namba nats. I'm guessing they're not setup to produce the power needed to compete with the current Italian marine .45 motors? I dunno. I've read that they are popular airplane racing engines.