I've had the license since I was 16. I had a corvair spyder with the turbo charged engine when I was 17.I built a 601XL just like that plane with a Corvair engine.
The problem with the Harley powered 601 was that it required a reduction gear to get the prop down to a usable rpm and the motor was underpowered. The 601 was designed for a engine producing 100-110HP at cruise.
It was that guys intention to produce the engine and everything needed to put it on the 601XL as a commercial venture. It was a huge fail.
Trust me, if a divorce is what you are looking for getting into building a plane will either lead to it or make it a mute point because you won't be in the house enough to notice you have a spouse.Maybe after the divorce