This guy is a craftsman. Apparently he took photos of a cut open engine at the Science Museum, worked out the measurements and made most of the replica engine in his garage - cylinders, con-rods, carburettor, valve train, camshaft, distributor, bearings, crank, bevel gear…
It makes 50bhp at 1300rpm. Peak torque is 180 lb.ft at 1000rom. It ticks over at 200. To start it you have to manually drip oil into almost 100 key bearings and friction surfaces, pressurise the oil distribution on the cats, flood the carburettor and turn in the electrickery circuits. Then kick start it. By which time the shops are probably closed.
