i have ported acouple of engines and u mostly just do wat the pics of the sleeve show u but do not do the crankshaft !!!!!!! u can stuff up the engine i had modified the piston,sleeve and crank and it was runnning sweet but wen i modified the crank it stuffed everything up and i couldnt get a proper tune as for the bits just use the cutting bits i used the round ball cutting bit and it worked good just make sure u dont go any faster than 12,000 rpm on the dremel because u will make ur bit go blunt speeding it up anymore aint gona let u finish any quicker well it might but then u gotta chip in another 50 bucks for bits (or u can just rip them out of the packet LOL)