Are you trying to replicate the K7DYY design without buying the transmitter?
If so, I would like to suggest that the designs on the class E web site are probably easier to replicate (there are no special parts), and these designs are also much more conservative in every aspect. The audio is also very likely to be superior (I will not comment further on this), and the RF amplifier design is much more flexible (will work into a wide range of loads). There are also other advantages.
Depending on your ability to locate parts and do metal work, you should be able to build a 400 watt OUTPUT transmitter for a few hundred dollars (
quite a bit less if you're REALLY good with finding parts or have parts on-hand ). I'm assuming a reasonable amount of parts hunting for tuning components, filter caps - things like that. Boards with or without parts are available for the low level circuitry. There is also a considerable amount of technical support available because many people have built these transmitters.
http://www.classeradio.com for info.
Regards,
Steve