Auto Zone Cruiser Accessories...screw covers $2.99 4 piece set.
They are by the Dice for your valve stems...or 8 balls or skulls.
I had to ream out holder(washer) with 5/16" bit,by hand,snapped right on.Still aint right but will do for time being.
Did you find them yet Mopar? Call me I will walk you through where to look.