I believe that 13,000 is correct for all stock 630 versions.....but as they stated in the page I posted they can be set 500-1000 lower for break in and perhaps better left that way for some customers. Some guys always set 500 below spec. The crankshaft bearings are the same for all 6XX saws and will safely spin past 15,000 without hesitation. I had a 630 Super II I ported before I owned a tach......PB came down one day with a bunch of saws and we had a grand time. He brought a new to him 630 which he set up at 12,500 with his tach.......I had tuned mine only by ear but since there was a tach handy I put it my saw......we were turning 14,400 and four stroking nicely. I turned it down to about 13,200, any lower and it was way to rich....we ran both 630s at the same time in the same sized wood.....mine ran out of gas when his was still half full!! I did some questioning of a couple of the known porters and found once modified stock specs were out the window so I turned it back up to where it had been and it didn't burn hardly any more gas than a stock one.......but the pile of wood on the ground was bigger. I sold that saw, it has been in the firewood business the last five years still going strong. It was a totally beat freebee when it came to me.....always called it my "Ugly Duckling Saw".