In the florida heat i run RP 10W40 and the ls1 likes it here.

My DD gets Rotella diesel oil yes diesel oil- has more cleaning agents, and works very well on every day drivers in hea, I wouldn't run this oil in the winter up north though as it is a bit thicker.

rotella also has a synthetic that works very well.

 

Amsoil 10w-40 or Mobil1 10w-40 - Both are good! My Z28 had 92,000 miles on it when I bought it 6 years ago. I switched to Amsoil 10w-40 mainly because Mobil did not offer that weight at that time. I have stuck with the Amsoil, but either would be fine in my opinion.

 

I run Castrol Syntec 10w-40 on my 140k motor because its a little thicker than M1. Seems to do the job and it drinks it less than with the M1.

 

Ok so I am wondering. This guy has 80 psi cold and 65 psi warm and i am guessing he is using 10w30. I've been using castroil syntec 10w30 in my car and i only run 60 psi cold and like 40 psi when its hot and about an average of 50psi. Is my pressure low or is his unusually high. I was planing on switching to castrol 5w40 next change. So advice on what to run would help out.

 

Mobil 1 SUCKS.

German Castrol, Amsoil, RP, Redline - All Group 4 Synthetics