Chainsaw Repair

So here's more on this saga .I pulled down the parts box of a couple junk 029 in the shed just to check things out .Would you believe the clutch side cover is a direct fit on this 034 .Stihl must have gotten their heads outta their butts because at one time every danged part was model specific on these things.Looken good down to a piston ,bar plate and air box cover .Oh yeah ,3/8" 7  small spline rim sprocket .Danged thing is set up for .325 .

Now why in the world would you use .325 on a 60 cc saw ?