How can I get a CFrame relative to a position and rotation?

I'm trying to consistently place my player exactly 1.65 studs above a brick, but my method doesn't incorporate rotation. It doesn't break, but I want it to seem like the player is sitting on the brick.

--rootPart is the HumanoidRootPart
--seat is the seat the player is sitting on
rootPart.CFrame=seat.CFrame+Vector3.new(0,1.65,0)

I'm really not sure how to approach this, any help would be appreciated!