I don't know what the 170Vb calls for, but here is what I use in my 220 6cyl gas engine.
I like Brad Penn, Penn Grade 1, Racing oil. I use the 20W-50 for the engine. It is a partial synthetic.
For the Central Lube System, I use Lucas 80W-90 gear lube. I do not use synthetic for CL system mainly because it has a odor that my wife doesn't like when she goes into the garage.
