it depends on your intake too - I recently put a set of these
Mr. Gasket 6861BG Fabricated Aluminum Valve Cover - Chrysler Small Block - Black Finish on my 360 with an Edelbrock RPM AIR-GAP - I had to "adjust" the inner valve cover edges to accommodate the runners on the intake. Thankfully at $123 for a set, they aren't
too expensive.