Haven't been on here for some time but as Oldstroker said you can run significantly lighter pistons sometimes with longer rods and if you don't need the ring stack for what you are doing lighter is better 90 percent of the time. Lighter stuff will take more stress off your assembly than the rod ratio will but it all helps and you are going the right directio with both changes on any given engine.

I run a lot of 6.000 and 5.850 for NOS or blowers and for extreme stuff sometimes back to the old 5.700 and they all seem to work just great. On a very small stroke engine I run the 6.125-6.300 stuff sometimes but many people believe that's loo long a rod to make good power believe or not but I do it to use a piston that's already a shelf part 90 per cent of the time anyway.There are other factors such as where the skirt shape is at BDC but this is usually designed into these pistons since they know the stroke and the cylinder lengths.

 

i disagree with that , rod angularity is changed by changing rod or stroke .
1.greater rod angularity = more torque less horse power
* obtained by longer stroke or shorter rod
2.smaller rod angularity = more horse power less torque
*obtained by shorter stroke or longer rod.

 

to calculate rod length add rod length to piston compression height plus deck clearance plus 1/2 of the stroke .

total should be right at deck height of block.

 

compresion is not affected by rod lenght
compression ratio is only affected by
1. dome size
2.combustion chamber
3.cylinder volume
*bore x bore x stroke x .7854

 

Prove it.

 

Wrong static compression is not effected by rod length, but dynamic compression is. Rod length effects piston speed and dwell time, these do affect dynamic compression. The LE2 setups are slated at 8.5 DCR because of my longer rods I ended up at 8.7 DCR not much of a difference, but enough that if not planned right could cause a street motor to not run on pump gas.

 

Ya can disagree all ya want. Between 5.7 and 6.2 there is NO difference ya can feel or see.
If ya haven't done the dyno tests your disagreements are just an opinion.Without CURRENT documentation it will just be an oppinion.

Look up Reher-Morrison(heard of them?) and look at the dyno tests they did on this subject. What they found out and proved to GM engineers is the same as I have seen.
If ya care to do a board search search on this subject ya will get a LOT of info.

Ya can influence the flow with different lengths.

"O" there is less than 1* change in angularity between the shortest and the longest rod ya can run in a SBC. Boy that is gonna make a BIG difference,HUH.