How do I specificly change the Y co-ordinates of:

void OnMouseEnter() {

Vector3 objectPos = transform.position;

Debug.Log(objectPos);

if(Input.GetKeyDown(KeyCode.Mouse0)){

Instantiate (_NONRIGIDCube,objectPos *1.05f,Quaternion.identity);

}
}

As you can see Ive had to *1.05f, this is not what I want however, I wish to only change the Y Value but keep the X,Z Position of the object. How would one go about doing this? Thank you

Vector3 newPosition = new Vector3(objectPos.x, objectPos.y * 1.05f, objectPos.z);
Instantiate (_NONRIGIDCube,newPosition,Quaternion.identity);