My engine builder had multiple National Wins sine the 60'S and has done extensive research into oils. He would be more technical and indepth of about what I am about to state.
He used to swear by Mobil 1 before they changed the formula a few years ago and take out the "Good Stuff". If you have noticed the bottles changed again in the last 8 months. Well, they put the good stuff back in and he swears by it again.
But, But, But...
If you are running a solid lifter cam big block, his number one choice was Pennzoil Racing 25W50. If you smell it you can smell the stick of the additive. The only other oilf that supposedly has it and the stinky smell is the Unocal Nascar 76 Racing 20W50. He never advised
synthetic and said he would only stand by the motor if I used the
oil he wanted.
Wellllllll,
CSX 4027 ran over 1500 track miles and never missed a beat, In fact, the new owner is still running strong and only using the Pennzoil 25W50.
Be it luck or coincidence, I go by his theory.
I ran 12.1 : 1 581Hp 522lbs torque and chipped at 6800
If you want to contact him to pick his brain be my guest
Cerrali Competition Engines 973-742-4972