How do i follow LookVector camera's X- Axis?

how do you implement camera's lookvector looking down or up to the part

Right now achieved getting the Left and Right camera's axis here's my script:

local cam = Camera.CFrame.LookVector
local Rot1 = math.atan2(-cam.X, -cam.Z)
local CamLookAt = CFrame.new(Torso.Position) * CFrame.Angles(0, Rot1, 0)
Seat.CFrame = CamLookAt --// the seat copy's my camera's lookvector but only left and right.

But now i want to implement up and down lookvector of the camera to the part.

which is the X axis and i tried doing this i have no idea.

Rot2 = math.rad(cam.X)
local CamLookAt = CFrame.new(Torso.Position) * CFrame.Angles(Rot2, Rot1, 0)

Keep the X and Z axis of the LookVector and set the Y to the Y (height) of the object you want to look up/down at.

Example:

local oldLook = Camera.CFrame.LookVector
Camera.CFrame = CFrame.new(Camera.CFrame.Position, Vector3.new(oldLook.X, NEW HEIGHT (Y), oldLook.Z)