Yeah I had cut a whole tank with that chain on the 372. It is on its 3rd tank of mix right now. It isn't quite broke in yet. It only pulls 125 lbs of compression right now. The 660 is being a pain to tune without the plug trying to turn whitish. It seems to lose quite a few rpms to get the plug to be brown.
That 660 sounded ok to me. Be wise, don't lean that big saw out, the mere second faster in cut isn't worth ruining it. The max rpm on that saw is 13,000
rpms. If its running 12,500 leave it alone. A saw that opens up under a load is all thats needed. It sure didn't sound like it was 4 stroking in the cut, it was running open. Turning up the rpms may increase your cut time alittle bit but the flip side is it may decrease the life of the saw.
Yes I thought that 372 seemed alittle dull there. They both run good, be happy...