Spark Plug Holder

Printed for a mechanic friend to hold old spark plugs for inspection as they're taken out or hold new ones with room to exchange for old ones to keep in order for inspection.
I extruded holes on the bottom for magnets to hold spark plugs in place even if it falls over and will still hold if upside down too.
I thought a v8 shaped holder with pistons on the front and back would be kind of cool looking.
The red arrow on top and the pulley on the one end designates the front so no cylinder or bank number necessary no matter what being worked on.