Back in the dark ages when I was growing up around a dirt track racing shop, there was a sign on the wall- - - -"Build 'em little- - - - -wind 'em tight- - - -get the chemicals just right!" Dad was always looking for ways to turn those flathead Ford V8s considerably higher RPM than his competitors. While most of the other guys were running long stroke crankshafts in the pursuit of higher torque, Dad ran shorter strokes, bigger bore sizes, and turned his engines much higher RPM than his competition. He also won a lot of races. Everybody was running the same kind of fuel- - - - -alcohol, with a heavy dose of concentrated hydrogen Peroxide- - - -which produced more oxygen in the combustion chamber than Nitromethane. It also allowed compression ratios around 11:1.
Since stovebolt engines have such terrible intake and exhaust port shapes, which effectively limits the volume of air they're able to flow, I wonder why nobody has explored the possibility of small displacement engines running at higher RPM while staying within the flow capabilities of the less than ideal cylinder head design? A 216 engine has a 3.5 inch stroke. Why not drill a 216 crankshaft for full pressure oiling, destroke it to 3.25", and run that crankshaft in a 235 or 261 engine block? Less displacement, shorter stroke and a LOT more RPM! A stovebolt built that way would probably sound like a bumblebee on steroids! That would probably require stiffer valve springs, and maybe roller bearing rocker arms and/or valve lifters, but it could certainly surprise a few people! A standard bore 261 with a 3.25" stroke would have 215 cubic inches, and probably be capable of 6K+ RPM.
Jerry
