From what I remember 064 and 066 (Flat Top) pre poly fly wheel all use same crank. In 1994 the crank changed from 12 to 13 needle bearings but would fit in 064 and all flat top 066's.
Then in 1996 crank was changed again for the poly FW. It will
not work in the 064 or flat top 066's.
Are you talking about the old dino oils or the new syn. oils....or both?
If not for AS I would have thought my 880 was running way to rich
when new, as with it hitting rev limiter it sounded something like
it was to rich out of the wood.
I may be wrong, but IMO I would not like the type of back plate you have.
The later flat filter and the HD filter pull air threw filter and into carb.
The type you have looks to pull air threw the filter and then threw
the back plate into the carb. With this type unless the carb...
When I get home I will try to take a few pics of my Non-HD 064 air filter.
I think back plate in almondgt pictures is the early type.
And from what I know it lets non-filted air come in from carb box.
Then Stihl changed the back plate to #10 as shown in mtngun picture.
#10 back plate is...