Hotrod46 gave you some strong advise. I always run zinc additive in my engines. Except my 7.3, International was smart and put roller cams in them. All the Cummins small engines are flat tappet. Common rails have narrow lobes and are known for eating tappets too.

This entire LS thing is tough for me. I'll spend a boat load to have a 400hp 354, but can have 800hp with a LS for less money more than likely. I keep telling myself it is supposed to be a cruiser, leave it alone. If I can get this 68 Buick in Oklahoma I found purchased, it'll get a junkyard 5.3, cheap turbo, and I'll daily drive it. Haha Once again, the train is off the tracks.