RE: Blown Glow Plug
It does seem to me that this is one of the least used things that will actually give you a good boost in power without much effort. I'm surprised the ducted fan people haven't been using them, and I wonder if they've caught on with the boat crowd. All it takes is a different head button. So I am surprised Sport Jetts aren't offered with the option.
It's not like Nelson plugs cost a bundle, either - $3 a plug is a lot less than an OS #8 or Rossi R5. Not to mention Rossi turbo plugs (same idea, a lot more expensive). The Nelson plugs are used exclusively in F2D Combat motors, and they are great in 1/2-As (with the Galbreath head), where they're a LOT cheaper than Cox 1702 glow heads or even Norvel Freedom XL plugs.
Henry will sell you the drills and taps needed, as well as head blanks, if you have a lathe. John Booker (CL Speed flier) has drills and taps, as well, and his own line of compatible plugs.