Wow, I'm really surprised by the amount of people who don't know what a transbrake looks like. You guys should go to the drags more often.
The transmission he speaks of is a TH400 Turbo-Hydramatic 3-speed automatic transmission with what appears to be a full-manual valve body, and the apparant transbrake. I'm thinking he has a ratchet-type shifter, but I could be mistaken. For those who don't know, this is an old General Motors transmission used in many of it's vehicles, and continues to be a popular(and rightly so...)transmission choice for drag-racing.