There are still a few oils on the market that have adequate levels of ZDDP.

• Shell Rotella T which is a conventional (mineral-based) oil that was originally formulated for diesel engines. Rotella T still contains 1,200 parts per million ZDDP, according to Shell – which is as much as five times the amount found in other oils. Don’t sweat it that Rotella was/is “for diesels.” It’s also an excellent choice for older, non-emissions controlled engines with flat tappet cams that need their ZDDP. Rotella’s also modestly priced and readily available at most any auto parts store. Shell also markets a synthetic version of Rotella that offers even more protection – as well as longevity and a 5W-40 viscosity for those who operate their vehicles in colder climates. Standard Rotella comes in a heavier 15W-40 blend.
• Another choice – in a full synthetic – is Amsoil which carries a line of oils with ZDDP in popular viscosities such as 10W-40 and heavier 20W-50.
• Redline oil is also still fine for older engines with flat tappet cams. Unfortunately, both Amsoil and Redline can be hard to find at your local store; but if you plan ahead, you can order a case from any one of multiple suppliers online and just keep a stash on hand.

Another option is additives.

GM used to sell an over the counter Engine Oil Supplement (EOS) that was just what the doctor ordered – and for only about $12 per bottle. Unfortunately, GM stopped making the stuff and it’s now very hard to find.

Luckily, Competition Cams does offer something similar – its Engine Break-in Oil Additive. Comp cams used to recommend this for initial break-in but now recommends that it be added with the oil at every oil change.