Ive been trying to figure out why i have such low compression (145 lbs 400ft above sea level). I don't use a base or head casket, i use silicone so the port timing is correct. every thing is sealed up nicely even my rings. so i check the squish clearance and basically i need to shave off about 0.2-0.3 mm to reach the desired 0.8-1.0 mm squish clearance that i read in the the two stroke performance tuning bible i have. This is with my 370 long rod motor 66 bore 54 stroke 115 rod. I am running a PD cool head with changeable domes currently got 19cc domes in it. sorry its long just want to make sure you know what i am working with. First is 0.8-1.0 a good clearance to have or is that a little to tight? Second would it be better to mill the head and how? or would milling the top of my cylinders be better so i don't mess up the seating area of the o-rings? I have tried contacting Rudy Kurtz (my builder) with no luck if you seen my other thread. So im just trying to take matters into my own hands now.