longer rods do more than decrease bore wear. A longer con rod makes the piston dwell at TDC and BDC longer, more cylinder pressure is generated before the piston starts to move away from TDC. Thus your motor will make more power. My basic rule of thumb, run the longest con-rod you can, without putting the wrist pin into the
oil control ring on the piston. I hope you know your deck height (measured, not what the book says it should be)before you order your custom pistons.