With all due respect, but I think those last comments are quite inappropriate;

1- You say I copied "your" head. Unfortunately I can't seem to find a conversion head for a MAC-10 KP2Y-C engine listed in the price-list on your site. If there was, I probably wouldn't have gone through the hassle of trying to make one myself.
2- When I made this head, I had never seen a model diesel engine, let alone one of your conversion heads in real life. I designed the head based on information and pictures I found on the internet (including this site)
3- As I don't own, or have ever owned, one of your conversion heads myself, I neither own, or have read, the directions that go with them.

I'm just a technically orientated modeler, who likes to experiment. That's why I thought converting one of my engines to diesel would be a nice challenge.

Don't get me wrong, I appreciate all the helpful comments, but I don't like being accused of stealing / copying someones ideas!

And besides, it's not that I'm trying to steal your business. Firstly, I'm only doing this for my own enjoyment and secondly I'm fully aware that the design and quality of this head is by no means good enough to be sold commercially.