I know some of the big name oil people don't help much with the ZDDP issue because of govt legislation. Some still have healthy amounts for flat tappet cams but I haven't followed that much to know who's oil is good. Since I bought a boat with tappet cams I need to learn about this until I change out the cams for rollers.

Is AmsOil one to have a good amount of the friction modifiers??? The PO was using that in this 357 and it has over 100hrs running fine.
My thoughts are to run conventional oil with the GM additive to satisfy the ZDDP needs. Any knowledge about this??

My first post here. I have 88 223 ss w/same engine. Myself and other friends with older 454's swear by Rotella T Triple Protection 15-40.

The engine builder who rebuilt my 85 454's instructed me to use straight 40 weight Valvoline racing oil. That was several years ago, but I still use it in those 454s.

Deff add zinc...and really any mineral oil will do...the 454 will run for years as long as its maintained properly... don't wastes your money on synthetic oil that engine wasn't designed for that straight mineral oil is what it thirst...overhead cams...then yeah synthetic is a must...oh yeah change it every 25 hours...

Valvoline racing oil has zinc all ready in it...notice the disclaimer " not for on road use" or something to that effect...it basically means it works to good and has all the lubricants in it the govt hates...its just cheaper to add Lucas oil additive and works just as good..

Kendall 20w50