Haven’t even run it yet as life has gotten in the way of MBs for a while. I did assemble it on the Runwell with the proper piston and the Grubee head that came with the cylinder. One thing I found that the Grubee piston (Super Rat engine)that this cylinder was designed for is 1mm taller. Than the piston I installed, so this is as assembled a lower compression engine. I am fine with that as I built it for longevity. If it lacks power there is an approximately 1mm ring on the head that can be milled off to raise the compression back to where it should be. I left the cylinder as received, but agree there is much cleaning of the liner in the ports to improve flow. I wanted to see how it ran as was. My guess it will run fine for my needs, not looking to for max output, but reliability and no extra work.