(yes, I'm reposting -- I realized that the title was a bit uninformative)

http://www.metalworking.com/dropbox/. Search on "cox_head".

Just finished running it -- ran through a whole tank of 10% nitro fuel.
I couldn't do that with the stock head; I think it just didn't have
enough compression. This head has stupid-high compression* -- it runs
better with a stack of three head gaskets than it does with none (I need
to try it with one or two).

_And_ it starts with a ni-starter -- Cox glow heads _demand_ a good dry
cell battery, and just sneer at you if you try to give them 1.2V from a
nicad.

* Note that it was built with more compression than the drawing
indicates, and wider fin spacing.

--
Tim Wescott
Control system and signal processing consulting
www.wescottdesign.com