I don't know what oil is speced for that engine, but a friend of mine bought a new 97 F-250 with that engine. He asked me what I would use for oil and filters and I told him Mobil 1 15w50 and a Motorcraft FL1A filter. He tows a trailer about 25% of the time and usually and does 5k OCI's. The truck now has over 200k and he has had no problems what so ever. I think this combo would work in warmer climate's all year long, but probably not a good idea in Kansas.
Agreed. The 429/460 family is a 30w engine unless it's a CJ, SCJ or Boss variant, modded, and/or you're tracking it. Start with 10w-30, and go to a 15w-40 HDEO only if necessary. Although . . . mine sure did run well on Kendall GT-1 back in the day.
My 1990 460 V8 motorhome specs 30 weight (can't remember if 5w or 10w), but I have been running 10w30 in it for a long time. Oil pressure runs 60 to 65 psi hot at highway speed on 10w30.
With (almost) that many miles on mine I typically use Chevron Supreme 10W-30, although I would consider a 50/50 mix of Delo 15W-40 for a long cross-country trip in the summer months &/or if there was any consumption between oil changes.
I have a '92 E350 Van with a 460 and I have been useing a 50/50 mix of Shell Rotella 5W40 and 15W40. All seems well so far and I have not noticed any oil consumption.
I took the Mobil Oil Recommendation Test assuming this engine came out of a 1989 F-350 with 200,000 miles on it also assuming it is 7.5L and gasoline. It came back as 5W-30.