For the best seal, Billet Specialties recommends the use of a cork gasket with all of the valve covers. 1 1/4 hole for breather/PCV. Short design - 2 3/4.
Note: If you're using roller rockers and stud girdles, you will need to use the Tall Design valve covers, which we have available here. We also have these same Valve Covers in Ball Milled.
The picture below shows 1 Short and 1 Tall Valve Cover. This listing is for a Pair of Short Covers. We have numerous other Billet Specialties brackets available, as well as many of their complete front engine kits.
We also have thousands of other High Performance Parts in our store. We want you to have the parts as bad as you do.