Unless you are turning more than 9k then the stock crank can take it. That full circle crank has RH threads on the magneto side, so you also need a right hand M11 nut for the flywheel. The difference in primary will not make a noticeable difference on a full circle crank.
In my opinion, always on a build (stock crank or full circle) you need to open the mouth of the oil journal with a drill bit so it is funnel shape. That will feed more residual oil to the mains where it is needed. Best practice is to change the spi seals as Graham mentioned.
Also match port the transfer lead ins and index your cylinder to get the best bang for the buck, whether you are staying completely stock, porting or kitting.