I was thinkin 'bout goin' synthetic in my D60+70 Just don't know how the Detroit will like it.
Your Detroits will be fine, I've been running Mobil 1 in mine for about 2-3 years. I used reg. oil for the first couple of months after I put in my new gears & Det.
Thinking about trying Royal Purple in my other rides when I get around changing the fluids on them.
