Don't know if Bem makes one for the 7.3L, but if you can wait a while longer the one from @BroncoHooves is a superior design. He's getting the diesel one out soon here, but the gas one will take a while longer. He doesn't have an ETA for the gas one, though, as far as I know.
(I've been beta testing a gas one for the last number of months and it's been fantastic. )
You can see how his works in the video in this post: