I agree with Rspears. You should use a high zinc oil instead of adding the additive. There are a few different brands, but I use/sell/like Joe Gibbs Driven oil. If the 350 was built to specs, the Joe Gibbs oil would be BR with a viscosity of 15W50. Use this for not more than 400 miles or 30 days. Changing the filter after the initial 30 minute cam break-in is preferred. After you drain the break-in oil, I recommend you continue to use the high zinc oil for proper protection. Joe Gibbs HR1 is 15W50, and HR2 is 10W30.