[submariner409]

Sevillian, Several oil companies make lubricants with ZDDP packages higher than starburst passenger car oils. Pennzoil, Chevron, Shell, Drydene.....maybe more, all make what is referred to as "Fleet", "Truck", "Marine", or "Long Life" oils in a variety of viscosities.....I know for a fact that Pennzoil (SOPUS/Quaker State) makes a line of fleet and diesel rated oils that are usually found at NAPA, Marine, and big rig stores. Their Long Life 10W-30 is a HD diesel package that gives me wonderful service in high-load marine gasoline engine applications......look at the pix of one of my Olds 455's in the adjoining thread about something like "safe to use synthetic...." - those puppies run thousands of hours at horrible temperatures and loads, and with both 15W-40 (summer, HOT, high RPM) and 10W-30 Long Life (year-round all-purpose) I have never had a complaint or bearing failure, and the engines run flat-tappet hydraulic RV cams and have never wiped a lobe.

Google "pennzoil long life" or "sopus oil" and surf to the product spec sheets.

Remember that Ford is running 5W-20 in their light truck and car engines........my F150 4.6L has 48,000 on it and uses not 1 drop of oil between 7,500 mile changes.