I just finished cutting down the crankcase for CH ignition and matching the flange to the cylinder. I am going to port the cylinder but decided to test it stock first. There are some differences in the new Homelite/Ryobi 30cc and the old one. I have new Ryobi and Homelite 30cc engines as well as old Homelites. The new ones come with 10mm WYC carbs, 30% more cylinder finning, a heavier crankcase/cylinder flange, thin ring piston, crankcase reinforced between the flange and bearing, and VERY mild porting. The transfer ports are divided and huge. I replaced the blower crank with a long shaft trimmer crank so I could use the standard CH ignition and hub. Matching the cylinder to the crankcase requires cutting 1/4" square notches and extending the original transfer notch 1/8". This more than doubles the original transfer area. The stock crankcase has notches for the 25cc cylinder. This masks the bottom of the 30cc ports and makes most of the charge travel through the ports in the piston. This should be a much superior engine to the old Homelite 30cc, it will be interesting to see how it performs. I am still searching for a steel header pipe and probably will have to make one.