I was fortunate enough to cross paths with a man that makes mini drag racing engines as a hobby (very long story).
His name is Ron Bement and he has to be one of the 10 most impressive people that I've ever met. Anyway, Ron was smitten with the Offenhauser (http://en.wikipedia.org/wiki/Offenhauser)engine and after seeing it as a kid when his father took him to the race track. After retiring as a machinist, he set out to make an "Offy" of his own.
Every part of this engine has been made by Ron using a variety of tools, CNC mill, metal lathe. He even had to make his own wrenched to be able to complete the project!
It would be impressive to me that he could make something like this that is a complete replica of the original but the fact that it works and sounds just like the original is even more impressive!
It took over 4 years of work for him to complete this engine and now he's currently building a new one which is a copy of the Ford Ardun.
Thanks for watching!