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481 Cu. in. Small block!


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Guest Anonymous

It's a neat oddity, but that's probably it. The rod/stroke ratio of this one is about 1.51, which is pretty bad. Good for wearing out cylinder walls, that's about it. Don't get me wrong-someone can take it and probably get ignorant power out of it, but that displacement is much more easily and better fed with big block heads. You'll be ET and dollars ahead to build a big block if you want a motor in that size range.

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I am entirely unconvinced on the whole R/S ratio argument. The max rod angularity for this setup is 19.87 degrees versus 17.7 for a stock 350. I don't see how there's a lot of increased wear due to such a small change.

 

There's a great plot in the Reher-Morrison book showing piston position for three different R/S ratios (1.53, 1.59, 1.63) as a function of crank angle - the three plots appear as a single line. The authors then go out of their way to dismiss the impotance of R/S ratio.

 

I agree with an engine this size will breathe a lot better through big block heads.

 

The ring package is really tight - the compression height is 1.013" . I'm not sure how streetable that aspect is, but I'd have zero problems with the R/S ratio.

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I agree about the R/S matter. Plotting the “crank-slider” model of piston displacement, speed and acceleration vs. crank position, and varying the rod to stroke ratio, reveals how little the piston kinematics are affected by changes in rod length. And the one or two degree difference in rod angularity - yeah, I don't see how that could be significant, either. Importance of rod to stroke ratio is one of those debates that will never get settled, simply because we just don’t have a rigorous way to quantify exactly what happens – in terms of engine output or cylinder bore wear – for different R/S ratios for the exact same displacement and block architecture. That leaves wiggle room for some expert engine builders to legitimately claim one thing, and for others to claim the precise opposite.

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