[Gunny]

Excellent post ... excellent read !!! My head hurts !

But it raises some questions ... I suppose that I'm looking for the bottom line answer, if there is one.

For my 90Z with over 100K miles

1) What oil is recommended?
2) What oil is acceptable? (not as good as recommended but won't damage engine)
3) What oil should be avoided?

I've used only M1 10-30 (previous owner did same). Do I need to start using the high mileage M1? M1 oil is readily available at Wally World & other places, but getting Redline or Amsoil will not be convenient.

Help please !!!!

George