what are the advantages of using longer rods
 

I seem to think the longer rods provide more power on the top with a lower piston speed and longer dwell at TDC.

something about leverage angle on the crankshaft :oops: :? :? :?

Yes, you are correct, the piston spends more time at top and bottom dead center meaning the dwell time is longer at top dead center the longer the rod. This allows more time for your fuel to be burned and push the piston down. This is the greatest advantage of rod length. The piston speed will be faster than a shorter rod between 15 degrees after TDC to 15 deg BBDC and so on.
Bruce

However... piston compression height LESS than 1.5 is not neccesarily a good thing...

http://victorylibrary.com/mopar/rod-tech-c.htm

for a coin it has two sides,some think pick a piston for the application,pick a crank then where ever the rod ends up that it is least important,,,,

i perfer to keep its value important so my opinion is the three parts must be all considered in the rpm and environment involved-whether n,a, or a power adder

Not as technical as DRTRCR22 's link but it sounds good

http://www.iskycams.com/techtips.php#2005

I swapped to a longer rod this past winter in my bbc from 6.385 to 6.535 if there is a difference on the track I've yet to see it ... and yes I'v adjusted looking for it :D

does it not have less side drag on the cylinder wall, creating more power too
?

That's debateable... the theory is less sidewall pressure, but for every change there compensation somewhere else...?

A prominent local engine machinist/builder believes long rods are good for circle track engines for bottom end torque...?

Drag race engines...? well, long rods usually have to be used to make up big bore long stroke combinations of big stroker engines.

Yes, less rod angle, less piston "cocking", less friction. Add longer dwell at TDC.
I run the longest rod I can.
Dave

My compression height on my short deck 565 is around 1.26. I have decided over the years that with a 4.600 bore the piston seems to rock to much so that one corner of the piston touches the head and the bottom of the skirt on the other side looks like it wears at a accelerated rate. I think Im going back to the .250long rod instead of the .400 in a short deck because of this. I dont think there will be a difference at the track.

Its been said before many times by very accomplished engine builders. The rod connects the piston to the crank, period. My thoughts, the only real benefit from a longer rod, is the potential for a lighter piston. Certian situations may favor a shorter rod, and certain situations favor a longer rod. For example, a big unrestricted slower port, tends to like the shorter rod, as is accelerates the piston away from tdc harder, yanking on the intake charge, speeding it up. Limited stuff, or smaller higher velocity ports, respond a bit better to longer rods, as the piston dwells a bit, and doesn't accelerate as fast away from tdc, balancing everything

Frank