Oil Additives Solid Cam??

I think Hughes is calling ZDDP zinc just because it's easier for most people to remember zinc dithiophosphate as zinc. I'm suggesting that if ZDDP is really important to you, look for the phosphorus content in engine oil because the ZDDP content is almost never provided.

The information you've given is anecdotal and I've tried to provide references for everything I've written. If you have problem with Rotella T, Delo 400, and XD-3 Extra, , obviously you should stick with the Hughes products.

I still think any CI-4/SL or CJ-4/SM HDEO will provide plenty of antiwear protection for flat tappet engines. I personally don't have a problem with using any name brand HDEO in my slant six.