I run mobile 1 high mileage full synthetic 10w 30 in my 302.
Wen I first got it it had 132,000 miles on it so I figured I'd put the synthetic in it. Its worked fine for me, no leaks, nothing. Im happy.
The only problem was that i found it to be a bit expensive for 5 qts, but I found out that walmart sells it for 22.50 $ for 5 qts. thats not a bad deal.