buffer (bÅ­f'Ér) Chemistry A substance that prevents change in the acidity of a solution when an acid or base is added to the solution or when the solution is diluted.
These Ford Racing Performance Head Gaskets are specifically designed for use with cast iron or aluminum cylinder heads on a Ford 289, 302, 5.0L, or 351 Windsor V8 engine.
Specifically, when repairing the cylinder head intake manifold attaching bolt holes on a 302/351w or 385 series engine, there are a few holes that can cause a particular problem for inserts. These are the holes that are drilled through the head intake face at a 45 degree angle. See the illustrations below.