I used 5W 20, just like what is stamped on the oil filler cap. I really cant tell yet, but my mileage seems to have gone down by about 1-2 mpg. Go figure.
Thanks for the replies. I figured it would be ok, I think the guys on this board are more knowledgable about oils and engines in general than other blogs.
My Hemi has the needed weight on the oil cap. Use that weight & you will be good to go............. These engines have a lot closer tolerances than even my old 426 Hemi & it asked for 10w30, I'm using Mobil 1 & changing between 4,500 & 5,000. Break it in like you plan on driving it...