Not a Rover build, but easily within the range of capacity for a (Buick) small-block derivative. Perhaps its the light which makes me pause, as several characteristics err towards that being on the flank of a P6 Series2. I'd not infer anything from it being badged 'S' as that implied - depending on market - it was either a manual trans or an auto! (and then I look at the other pictures...) Yves and I have had, or still maintain unusual P6's within our fleets.
Guy that owns it is the 2nd owner. The original owner had the the engine done to stage 3 tuning. Told me it produced 300hp. It has a 5spd manual, but never used it! He also told me that there were 3 made.
Oh....3 made - by whom and when? Not Rover.(but do I need to know?) There are dozens of big engined P6's about nowadays, and 300 is not a surprising number, but why? 135 was enough to shove a Range Rover about, and P5B is rated at 165 if I recall. Horsepower (SAE or DIN or any other rating system) is nothing if there is no torque. The 77mm gearbox is a near direct replacement for the P6 manual 4 speed and gives a useful over-geared top. But the P6 (and P5b) are just beautifully engineered cars, quiet and with a sublime ride to go with it, If I wanted a sports car with a hardcore Rover V8 then possibly a TVR? The Repco V8 F1 engine is another loose derivative of the buick small block...so could be Rover engine...Europe used the 4.6 as the biggest production sweep, but were there bigger ones in Aus? what did P76 use? Best stop, going down a rabbit hole!
I was told they were custom built, by who, I didn't ask or care as it was a long time ago! The current owner did say that the crank was done in Detroit, I presume in the Buick factory. Its a well used but looked after car.
Yes, you can buy all sorts of tuning stuff in the states, their volumes were astonishing, so even a dead duck like the buick which only lasted 3 series production years in the early '60's is still supported quite well. Its no coincidence that the engine shares common 'transfer' dimensions with pre and post engines. As a consequence the production equipment didnt need wholesale replacement with the outgoing engines and then the replacements...so its quite plausible that stroker cranks for something else are readily adapted to fit. A quick google tells me the 215 ci will actually go to 307, which equates to a bit over 5.1 ltr.
