Rod Ratio, 400 Chevy.
Personally I don't think there is an ideal rod ratio, what's good for one engine is not necessarily good for another. I feel that the effects of rod ratio are very much overstated but that if it does have a measurable effect it goes something like this:
If you have a large volume effective intake tract and a rather restrictive exhaust port it's better to have a lower rod ratio, a shorter rod and a longer stroke. Why? Because making the rod shorter makes the piston approach and leave the area at or around TDC more quickly but it produces the opposite effect at the bottom of the stroke, the pistons motion changes more slowly with the shorter rod. What this does is work the intake side harder while giving the exhaust a little bit more time to do it's thing. The exhaust lobe can have a chance to get the valve open a little bit farther before the piston really gets going back up the cylinder thus helping out the exhaust side.
Does a 4.500 stroke 6.700 rod combo work? Absolutely.
Remember a 400 Chevy engine has a rod length of 5.565 inches with a stroke of 3.75 or 1.48 and they ran 100,000 miles easily enough.