Example. Engine is 4 inch bore with 4 inch stroke. Rod length is 6.500 inches. Compression ratio is 10.0:1. With all else staying the same, what will be the effect on the compression ratio by installing rods with 6.550 length?
Please dont put too much into this, i.e., deck height, piston to valve, etc. It is just an example.

one would have to make some assumptions as to chamber size, valve reliefs etc. but lets say you had a 77cc chamber and 4 cc's of valve relief and your piston was down .05 on the 10-1 combo, adding .05 to make it zero deck would make the compression ratio 11.167-1

Thank you Dan. I was having a brain blockage, thinking a change in sweep was invloved. But realize that is incorrect, as the stroke stays the same.