You want it done right watch Joe Dunnrite. In this 2 part series, Joe converts his 38 year old Stihl 038 AV chain saq from the old style sprocket drive to the new rim sprocket. Joe runs into trouble but don't fret, stay tuned for part 2. If you want to convert your older saw with the old style sprocket, you will need Stihl Part Number 1119 007 1003 drum kit and also need a clutch drum bearing part number 9512 933 3150 (you can use the old 2 bearing set if you want) and an oil pump drive gear part number 1119 642 1501. Joe says if you want it done right, he recommends using Stihl parts (he does not get anything from Stihl to say this!) however you can buy aftermarket parts that will do the job at a lesser price. When installing the oil pump gear, make sure the drive gear mesh is smooth, Joe says you can loosen the three bolts that hold the oil pump to the housing to adjust the clearance between the gears so it is smooth! Watch Part 2 as Joe makes a minor modification to the cover plate to allow proper clearance for the oil pump drive gear; an easy simple fix. You want it DONE RIGHT! Watch Joe Dunnrite!