Japan has or did have some really strange laws concerning keeping a car on the road. They might be different for classics but normal cars you go to showroom and buy. After 5 years you have to replace anything that retains a fluid like radiator hoses, oil seals, grease seals, gaskets on the entire vehicle. So it costs more to keep on the road than to scrap out and buy new. That is why so many get exported to countries with RHD. It is said the law was put in place to bolster the car companies sales, new car every 5 years regardless of miles.
I have a family member that buys the Nissan Skylines and ships them back to U.S.. Takes a little paperwork but you can do it. They can no longer drive them and have to either part out or scrap.
I know some of European countries also are strict on the condition of vehicles and don't allow rusty vehicles to obtain a license. Got to fix all the holes.
Thanks for posting the video. You could export the drive train out of the 429 car.