This particular engine, an 18RGU, was found in a Japanese junkyard with about 30,000 miles on it. Crankshaft bearings and gaskets were replaced with a combination of locally supplied 18RC parts and 18RG items obtained through Toyota in England. The dual Weber DCOE look-alike carburetors had self-destructed and were replaced with a Corolla manifold and single Weber. The intake restricts power, but one can hang in fifth gear at 25 mph, floating like a DC-3 on landing approach.
that was a write up on a web site in case you are interested