I was wondering what engine that might be, as I’m familiar with the 3.5 lt Rover V8 and it looks very similar.
Courtesy of Wiki...
And some text info... maybe the last sentence (below) is a clue???
The Rover V8 has long been a relatively common engine for
kit car use in Britain, much as the
Chevrolet small-block V8 is for American hot rod builders (though many British hot rods have traditionally used four cylinder engines, like the
Ford Pinto and
Crossflow units). Even in the US there is a strong contingent of builders who select the Buick or Rover aluminium V8 engine for use in small sporty cars like the
MGB and the Chevy Vega. The 1964 Buick iron-block 4,920 cc (300 cu in) engine had aluminium cylinder heads and a longer stroke crankshaft, which with modification can be used with the Buick 215 or Rover engine blocks to produce a high-output, very light weight V8 with displacement of up to about 300 cubic inches.
The 300 crank in the 215 block yields 4,260 cc (260 cu in). Traco in the USA were prominent builders of such engines.