At the speed stovebolt engines run, the difference in weight will not be a factor. If you were turning it 6,000 RPM with a very radical cam profile and had to worry about valve float, things would be different, but that 261 will hand grenade itself long before valve float will become a factor.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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