Home built engine in old Harley Davidson Hummer

My neighbor built this little engine in the machine shop in his garage. He built everything except the cylinders, which are some old Briggs cylinders if I remember right. He built everything including the transmission. Notice the little drip oiling system mounted back by the rear cylinder that feeds through the copper lines. Also the U-shaped intake manifold that feeds from the carb on the other side. You gotta hand it to this guy, he is one hell of a machinist and fabricator.