Nice to see some more people having a "go" at this engine.
I've seen reports on the newer version and the performance is not better than the "old" one...
The only visible changes are cosmetic to the case, the rest looks the same.

The glow version is weak but quite easy to bring up proper power, the head is a two piece (as said above) and it is therby quite easy to remake the combustion part as there are no threads to make.

Places to get more power from on the older glow versison:
- make a head that takes turbo plugs
- enlarge the throttle barrel
- enlarge exhaust outlet
- remake the case so that the ports in the case and liner are matching

These changes will take the power right up to pair with the Norvel .074, i.e. around 16700 rpm on APC 7x3.
Here is a short movie of it pulling a work bench: http://www.rcuvideos.com/video/Film-TT-Gp07-wmv

I've since then used it a scooter and the power is more than enough, rogs of grass at 1/2 throttle and idles around in the sky for a long time...

I do have one issue though. The plain bearings are rapidly being worn out! [:'(]
I've used fuel with 20-25% of castor and the crank gest sloppier for each flight, just a warning as a diesel version may put even higher forces on the crank. Both from higher compression and larger prop. I don't want to discorage anyone here but just be aware of this weak point.