I may just have to see this to believe it, But I think the 056 was a slightly higher revving saw than the 066 and 660. I am not certain about the engine speed though so please dont take my word as the word of god, thats Kevins word that counts on these things. But then again, I have seen some saws that will outperform the fanciest and most heavily modified saws out there, Like the 090 will out do the 088 by nature simply because the 090 is a larger engine class, at 8 CID not 7.42 or so. Its just larger. But my words are just that, they are not certified to be accurate. Just hope I am not wrong about too much, I dont have much knowledge on saws older than 10 or 15 years old.