posted June 11, 2004 07:42 AM
In my opinion, the main advantage is in the weight of the piston. Most aftermarket 6" I beams are lighter than stock 5.7s. Pink rods are even heavier. A 6" piston is approx. 50 grams lighter (or about 1 pound less for the whole set) and that will make a difference in how the motor spools up and revs down.
The theory of dwell at TDC and what not is such a minor variation it's really not that significant compared to the weight loss.
posted June 11, 2004 12:48 PM
It all depends on what track your running and where you want the power. Shorter rods make more torque off the corner but sacrifice longevity and high rpm power. Long rods promote a higher rod ratio *length of rod divided by the stroke of your crankshaft *****alot think 1.8:1 is optimal******** the higher ratio gives the torque at higher rpms and implies less stress on the sides of the cylinder wall. A longer rod decreases piston speed and its relationship to duration at top dead center. This allows for one to take advantage of a steeper ramp on your camshaft as well. (Giving more time for chamber to fill and get more mixture inside). More specific? For instance an indy motor usually has around 2.5 to 3. rod ratios. This is for the high rpm narrow rpm band that their intended for. A farm tractor has a long stroke and a short rod for low rpm torque. Is this helping? On small chevy's 6 inch is normally ok on larger *383 and above* engines. I would stick with 5.7's on less than that or 3/8 milers and below. My opinion. Greater than 3.5 stroke 6inch less than 3.5 use 5.7.
posted June 11, 2004 02:32 PM
oh boy....here we go again....if you want to get off the front of the push truck quick, use a short rod. if you want to drive that sucker off the the back row to the front, use a long rod.....the longest one that you can fit in it!
posted June 11, 2004 05:04 PM
Don't really think in our type racing that the diff from a 5.7 to a 6 as far as torque goes is that great but less weight and less stress on the rotating assembly therefore as said before longevity I do think as outlaw said there are rod and stroke combos that can make a big diff just not this one in a 350 which I assume you're talking about