Originally Posted By: psiclone
My friend just built a 454 chevy with a flat tappet cam. I suggested Rotella T synthetic 5-40, Mobil 0-30 with Red line break in additive, or just Red Line 0-30. The cheapest would be the rotella T but he just spent 4,000 on building this engine. What are your opinions?
For a 4x4 cam (mentioned later) I would think that Rotella synthetic would be fine. Cams intended to preserve low-RPM power don't usually have obscene spring pressures and ramp rates.
On the other hand, older Chevy engines are harder on the cam/lifter interface than Fords, AMCs, and Mopars due to their smaller-diameter lifters, and the BB Chevy is even worse due to the awkward pushrod geometry. So its probably best to err on the side of caution. Any HDEO (Rotella, Delvac, Delo, M1 TDT, etc.) will tend to have a bigger dose of Zn/P and other additives to do the same job. But there are also still SL rated passenger car oils out there that should do OK. Royal Purple is staying SL with most of its line, as are many of the "high mileage" oils like MaxLife... at least for now.
Personally I would avoid the "Racing" oils if this engine is going to be driven on the street a lot because they tend to short-change the detergent/dispersant additives. They might be OK with a ridiculously short oil change interval.