you'd be best to have the cylinders honed to get rid of the ridges...or your rings might burn out quickly after a few good redlinings...higher rpms the piston travels a lil higher due to flexing....with the eta head,its not used to winding that high...but with headgasket problems comes overheating issues....pop the valve cover,if theres a lot of yellowing on the metal....walk away....but if its good,you can make a mean lil motor!!!