Or B) make a stack of sheet metal - like a deck of cards - the same size and thickness of the valve assembly. Either spot weld the whole stack together, drill a hole through the middle and use a nut and bolt, pop rivet, or otherwise fix the entire affair together so it doesn't blow loose.
Then again, if the stack would be trapped in that space between the bottom of the valve cover and the head, then fixing it together might be unnecessary. *shrug*
No real way of telling 'til one of us pulls sh!t apart and looks.