ok so i bought a 99 s series wagon apologies its not a sedan but theres no forum section for it.
anyways i put a 96-97 motor in it with a 94 valve cover. my question is which valve cover gasket should i use.
a- https://www.autozone.com/external-en...e+cover+gasket
option b- https://www.autozone.com/external-en...e+cover+gasket

 

Everything below is for the DOHC only

94 valve cover as in aluminum?
I would say use the 94 valve cover gasket or it will not necessarily fit in the groove of the valve cover from 94.
It's a custom-shaped seal up against a flat surface. Shouldn't be a problem and I know people used to run the aluminum valve covers on the second generation S car engines.

You may find that the 94 cover has through holes to attach additional bolts that the 97 plastic cover does not. Use this to your advantage and get a few extra bolts.

Having driven DOHC S cars since '92, the aluminum covers have more attachment points, but as long as you have clean mating surfaces, follow the tightening order and do not over torque things, they both work just as well.