first ....no

second.....there is theory behind rod length...
it all has to do with piston speed...a shorter rod has a faster piston speed (going near and away from TDC) while the longer has a slower piston speed.....

what does this mean? well a shorter rod can take advantage of a larger head better due to increased speed.....while on the other hand a longer rod is slower and spends more time around TDC absorbing more of the power from combustion....putting a little more to the crank.....

Although with a 6in rod you will lose a little torque down low but not much but will gain it on top....

Find the article in HOT ROD "the 350 chevy should have built" this will help you understand this more....