I'm wondering if He stretched it himself making it into more of a loop frame. It looks like there is a weld on the down tube by the head tube or maybe that is just the way they lugged that particular frame.
Maybe the small section of tube cut at the motor mount was the original down tube? Cool looking bike, that's for sure.
The downtube is modified- that was done by me some time ago. The rest of the bike is stock. The bike is a 1980's Worksman that I picked up- $50 for two if them. The other one is in my storage barn and might see similar treatment one of these days