The early Toyota L6 "F" engine, used 1955-74?, is not a copy of the Chevrolet 235 entirely, but a similar head and combustion chamber design but "scaled up" to the larger G.M.C. block dimensions but few interchangeable parts. Not "stolen", manufactured under license.
The later F updated the head design to parallel valves, and finally to 12 port.
No, the Toyota head doesn't fit either engine: too big for the 235, and the water, bolts, oil, etc. don't line up for the GMC.
