Stihl Big Bore 090 Chainsaw

The removable cylinder head to the 10 cube 090. To your right a standard 090 piston on top of a 10 cube barrel and piston.

Standard 090 = 137cc 10 cube version = 159cc

Notice that the 10 cube cylinder has 4 through bolts and 4 stud bolts

It would be great to see the porting layout on the 10 cube