No idea.
Figure 2 hours labor and a tube of Permatex Black RTV or MB Sealant.
( if we are talking about the vent covers )
If valve cover gaskets, then 1 hour labor and $10-$25 for the gaskets from RockAuto.
Home, folks think I'm big in Detroit City.
From the letters that I write, they think I'm fine.
But by day, I make the cars,
and by night I make the bars,
If only they could read between the lines!