The following information was found on the Mobil 1 website:
Question:
Does Mobil 1 Contain the Additive for Flat Tappet Cams?
I build a few engines a year as I do muscle car repairs and I have been having a lot of camshaft failures. I just read that it is because the
oil no longer has the additive for flat tappet cams. Can I use Mobil 1 to break in fresh rebuilt engines of '60s and '70s tech? Is it too slippery for new ring break-in? Will it give protection on new cam and lifters?
Answer:
For older, flat tappet engines where wear may be more of a concern, we offer a number of
oil products which are higher in phosphorus than API SM/ILSAC GF-4 oils. These include Mobil 1 15W-50 (1,200 ppm), Mobil 1 0W-40 (1,000 ppm) and Mobil 1 High Mileage 5W-30, 10W-30 and 10W-40 (900 ppm). For all newer engines and flat tappet engines in normal service, API SM/ISLAC GF-4 oils are preferred for better fuel economy and for the protection of catalytic systems with lower phosphorous (800 ppm