First of all you must decide what rod/stroke ratio you want. Then buy some rods and calculate the hight of the block.
Now you got 90mm stroke and 137mm rods. that means R/S=1.52.
If you want to better the R/S ratio you must lower it and that means shorter rods=lower block.
Now you got 90mm stroke and 137mm rods. that means R/S=1.52.
If you want to better the R/S ratio you must lower it and that means shorter rods=lower block.