Castrol GTX 20-50

My Dart has a roller cam so I'm not too worried about the oil for that, but I have an 85 Toyota Supra with flat tappets. I used the Mobil1 0w-40 Full Synthetic because I felt 50 weight oil would be too heavy. The 0w-40 has 1000 ppm phosphorous and 1100 ppm zinc, so it's probably fine.

Here's the link to the product guide. I'll also include the document so when someone finds this post 10 years from now and the link is broken they see what I was talking about