You are probably safe with a 5 year or 50,000 mile belt replacement interval. This is a hotly debated routine but If I owned a 328 that is when I would change mine. I manufactured a new timing belt pulley and tensioner set up for my 82 308 and plan on 10 year 100,000 mile intervals since it uses the latest design HTD, HSN belts. At the first 30,000 miles I would adjust the valves and after that adjustment they will probably never really need it again. I overhauled my engine recently and of course adjusted the valves and do not ever intend to adjust them again.