well , im impressed and im hooked cad bad , i have had 55 for long time she crapped out on me other day 1996 model , so i took it apart took cleaned up cylinder with some acid had one bad score ,only one , thought this is time for some port work so got out dremel ,i figued if i mess it up who cares has bad score on it anyway. is this a closed port saw ? unlike 262xp piston is solid only open at bottom on piston and cylinder is diff. than 262 well i kinda went little wild with dremel widened intake about 30 thouands and exhaust even more could not do much with comp. just thinner gasket did not change port top or bottom just whole lot of widening going . i figured if it dont run, i would get new cylinder took it on hill tonight and cut about 2 trees up man it just screams smoken tons of power and speed really big diff. in chain speed i would have fooled with squish but way clyinder is made you would have to do some machine work , no way to do it, opened up muffler i dont have a tach but it is humming some rpms .