The Stihl 070 was the latter version of the Stihl Contra "1106" series. (Keep in mind that "1106" series started with the Contra and evolved through those saws and included "1109" which would have been the 66mm top ends.) Read link above {1106-1109 evolution} for a wider look into that. (Link coming soon).           It really helped to set a standard for the 070 being the predecessor to the Stihl Contra that was a very well made machine and saw use/sales in nearly all countries cutting wood. The 070 is still being used in Africa and South America where there is heavy logging and sold as a MS720. There are even complete copies available out of China and being a vintage labeled saw, all parts for the 070 are available from aftermarket sources. 

     A quick look at the difference in the 070 to the 090. 

The 090 has a 66mm (137cc) top end (piston and cylinder) with a large 6 shoe clutch. 

The 070 has a 58mm (107cc) top end (piston+cylinder) with a smaller clutch.

(Either top end or clutch can be interchanged as the rest of the saw is the same.) 

They are the same saw besides those two differences. So basically the 090 is the factory big bore to the 070.

     These are easy saws to work on and to keep going. With all parts still readily available, the 070 seems to be over shadowed by the 090 a bit too much.  The 070 is a great saw for bucking large logs or works perfectly at home on a chainsaw mill.  All around it is a great saw that was made to last.

 

Note: The saw in the 2 videos below was used heavily for a solid year and was used before I obtained it.  The current owner has been using it just as much if not more.  The funny part is,  it still finds its' way back to our wood pile when there's an abundance of large logs that need bucking up.