[img]/phpBB/images/smiles/icon_cool.gif[/img]with its favorable rod/stroke ratio, the 289 breaths very well despite the restrictive ports in the head. it isnt so much the shorter stroke, but the better r/s ratio that helps the breathing. one good example of this is bob gliddens pro stock engines from the 70's. he used modified 351c 4v closed chamber heads that would feed much larger race engines very nicely. considering the fact that the ford competition in the same class also used similar heads, and head mods, why was glidden so successful with his combination? he overbored his blocks .080 over(yes they were highly modified to allow this), and destroked his engines to 3.25" giving him a much more favorable r/s ratio to his competitors. so even when you have heads that not just breath but hyperventilate, r/s ratios are important.
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