I have got a 670 champ that I bought in the early 90s to cut timber with. One of the best darn saws I have ever had the pleasure of owning! I still have that soul today and all I have done to it is put a carburetor on it. That soul of yours really sounds great, and seems to run extremely well!
Man, you've been building so many nice strong saws lately. This one doesn't sound that mean. But, boy does it eat hard wood. I guess the bite is harder than the bark. That big oak didn't even hardly slow it down at all. Nice job!