You will likely need to focus on the timing belt , cam gears, and camshafts.
For a detailed list of every part needed for every story car, you can check comprehensive guides on the Steam Community. Auto.mechanik.SimulГЎtor.2018.VR.ДЌГЎst 2.rar
Use the examination mode to highlight parts that are "bad" (indicated by red/rust textures) before you start teardown. You will likely need to focus on the