[Alex V.]

I've seen a number of flat-tappet engines run many miles (not just toys/cruisers - everyday working rigs) without ZDDP additive with no excessive cam wear or failure - a good oil changed at adequate intervals should protect the stock, low-lift cams in our trucks after break-in, but a ZDDP additive or oil that's already higher in Zinc (some dual-rated gas/diesel oils or special hot rod/classic oils) won't hurt. Seafoam is a good periodic additive, but I don't use any additives full-time and run 89. Our truck's stock engines are nearly all low enough compression that knock resistance isn't much of an issue, but I've just had too many occasions when new and old vehicles ran better on plus than regular it's now habit to punch the middle button on the pump. Burns cleaner, runs cooler, etc.