Inliners International Forums General Discussion Engines Highest RPM for a 250

A 250 (stroke: 3.53", rod: 5.7") at 7,500 RPM is only 119,000 f/s/s piston acceleration.
9,000 is far worse than it appears at first impression, because the inertial load varies almost as the square of the RPM. 9,000 is 171,000 s/s/s, 44% higher stress.
A 292 (4.12", 6.76") at 8,800 is even worse at 190,000.