[Anthony]

Originally Posted by blykins

Hondas, Toyotas, M3's, etc. are not swinging 4" and 4.5" stroke cranks....nor do they have 4" or 4.25" bores. That's not really a valid comparison. None of those are 8 cylinder engines....and none are swinging the weight that a nicely sized V8 has to swing.

You're right about the heads, cam, and intake not supporting enough flow for a higher inch motor.

However, with flow rates and volumetric requirements all being the same, there is a cap on rotational velocity and rotational acceleration with longer stroke engines.

Compare these two engines:

A Nextel Cup engine. 4.125" Bore, 3.3" Stroke.

One of the FE's we were talking about. 4.310" Bore. 4.5" Stroke.

Do you honestly think that if you could supply the FE with an equivilent head/cam/intake package as the NC engine has....that it would make horsepower, much less survive, at 9000 rpm's?

You've heard the NASCAR guys free rev their engines.....you think you could make that 4.5" stroke (with the undersquare bore) engine rev that quickly? Highly unlikely.

I suppose you could model it by looking at a figure skater. What happens when they're doing their axials and they stick their arms out? They automatically slow down. When they tuck their arms back in, they spin faster.

Basically same principle. They are spinning weight either further out away from their body, or close to their body.
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Your comparison of a figure skater and her arms is even a less valid comparison. I think the figure skater is a good example of conservation of angular momentum which doesn't really relate to acceleration.

Pro-Stock motors run 4.5+ strokes at 9000 rpm's, ?1200 hp normally aspirated. Have you heard these prostock guys rev their 700 ci engines? They sound to rev pretty quick to me.