What oil are you running in your 500HP's?

Mobil1 15-50

valvoline vr1 racing 40w

+1

Please read ! http://www.amsoil.com/shop/by-produc...50-racing-oil/

i ran 15w40 rotella in my 500s. my builder said they were the cleanest engines he's ever disassembled

Was told by a friend of mine and engine builder that Rotella is one of the few oils that still retains zinc. A must if you are running non roller cams and something to be aware of when choosing an oil. He has seen an increase in cam failures in recent years in a rate seemingly directly proportional to the rate at which zinc has been backed out. I run Merc 15-40 in everything or Brad Penn, though i think i heard Merc is removing zinc as well.

Merc motor oil is made by Citgo and the reason for one of the motor oil's offered by merc to have the lower leverls of Zinc and phos is because of the catalyst engines, Zinc and phos coat the catalyst core over time from blow by and degrade the core. Merc came back out with another Service Bulletin switching back away from the 20 w -40 syn low zinc / phos oil. I have all the Merc SB's.

interesting, i knew it had to be an emissions reason to remove the Zinc and Phos. Its unfortunate other result is cam life issues.

I have also had exceptional results with rotella, another great choice.