>From my favourite M3 crowd...
>http://www.e30m3performance.com/tech_articles/engine-tech/rod-ratio/kin2.htm
>
>From page 2: "As the rod gets shorter, on the other hand, the
>max. piston acceleration is increased, but only at TDC. At
>BDC, the piston acceleration is actually reduced by a shorter
>rod (at least intially). The piston acceleration curve also
>begins to form a characteristic "double-hump" shape. If one
>were to keep making the rod shorter until it was only as long
>as the crank arm radius (a shorter rod than this would prevent
>the crank from completing a rotation), then the piston
>essentially would come to a "sudden" stop at 90° ATDC and
>it would "suddenly" start moving upwards again at 90°
>BTDC. These sudden stops and starts lead to infinite
>acceleration at 90° after and before TDC, and this is what
>the double-hump is starting to show."
>
>>>But wait, there's more!<<
>
>This man has forgotten more about engines then I think that I
>will ever know. Great guy, and a guru, if anyone can be called
>that.
>
>http://www.iskycams.com/techtips.html
>
>"In fact, this may surprise you, but I know of a gentleman who
>runs a 5.5" Rod in a 350 Small Block Chevy who makes more
>horsepower (we're talking top end here) than he would with a
>longer rod. Why? Because with a longer dwell time at BDC the
>short rod will actually allow you a slightly later intake
>closing point (about 1 or 2 degrees) in terms of crank angle,
>with the same piston rise in the cylinder. So in terms of the
>engines sensitivity to "reversion" with the shorter rod
>lengths you can run about 2-4 degrees more duration (1-2
>degrees on both the opening & closing sides) without suffering
>this adverse affect! So much for the belief that longer rod's
>always enhance top end power!"

Nice quote by someone else. I can give you 100 quotes by other people with 350 engines that will tell you that long rod motors will give you slightly more power. There are more arguements that long rod motors will produce more power than short rod motors will. That is of course to a point. For example, a chevy 350 motor, as you quoted earlier, uses a 5.7" stock rod if I remember correctly. A 6" rod has been proven to consistantly add more power than a 5.7" does. Not much, but if there is no cost difference then why not go for it... With a 5.5" rod, even if that guy were able to gain a tad bit more power than you did with a 6" rod by gaining a few degrees in intake duration, what you lose in the durability of your engine would not be worth it. And by the way, he would not have the ability to increase the intake duration without aftermarket cams. Using stock cams only, which setup do you think would make more power? I highly doubt there are many if ANY 2gnt guys that are looking to trade a significant amount of engine life for just a touch of extra HP.

Also, where you are gaining a extra few degrees of duration at the opening and closing of the valve, you gain more airflow when it counts with a long rod WITHOUT using aftermarket cams. Peak piston velocity is usually somewhere around 75° ATDC and since most cams cannot fully open the cam until at least 106° ATDC, it leaves the valve as a major obstacle when airflow demand is at its greatest. By delaying peak piston velocity, even if it's only 1 or 2 crankshaft degrees, it can allow the valve to open another 0.010-0.015", before peak airflow demand is reached. Not a huge help, but a step in the right direction.

>Pot, meet kettle.

Whatever, maybe if you are talking about pant sizes. I'm done arguing here Mr. Knowitall.

Matt
1995 Eclipse GS
2.0L, S16g Turbo, 8 Injectors, 26psi

1998 Eclipse GSX
2.3L Stroker, AEM EMS Converted to Speed Density, FP3065 Turbo, 35psi , and so on...