Originally Posted By: crazycrak
Is there any other high zinc and phosphorous oil that is converter safe?
As Astro pointed out, those engines were speced for SF or SG, which were higher ZDDP oils, and as you point out, there were cats at the time. With the Chevys, I'm mixed on the ZDDP issue. With the millions of miles I put on Chev small blocks, they ate cams, regardless of ZDDP content. My experience with respect to cats at the time is irrelevant. We ran LPG, which was a totally different animal, and the cats were removed the first time any exhaust work was done to the vehicle.
Aside from that, there's nothing wrong with choosing safe over sorry. If you can get the Brad Penn at a sensible price, why not? Another option is Rotella in 10w-30 or one of the XD-3 or Delvac options. If you want synthetic, there are plenty of choices, including TDT, Delvac 1, RP, GC, and on and on for higher ZDDP oils.
I'm going to mention additives, even though I've spoken against them regularly. Right now, the F-150 in my signature has Comp Cams zinc additive and SM/GF-4 QSGB. I'm doing that because it was a reasonably priced alternative (under $10 for the QSGB and around $12 for the additive - cheaper than running, say, a sump of RP or GC). Ideally, I'm just going to run a 5w-30 conventional HDEO, which will have enough ZDDP, a sensible viscosity, and a competitive price.