Vasek;
Be carefull cutting the skirt on the ex. side. If you go up to high, when the piston is at top dead centre, the ex port will be exposed to the crankcase. Put a mark on the piston at the bottom of the ex. port and don't cut above that line. Use something like a nylon tip marker, don't scratch the piston. I'd practice on an old LA motor. They are a mild mannered engine and will show an improvement when modded if done properly. If it doesn't work you havn't lost much