Fel Pro I agree valve covers with tabs to lock the gasket into the cover are best. I had an experience a few years ago with a set of fabricated valve covers as it blew a gasket out top end of the track no damage but I have found that valve covers that are smooth on the bottom with no lip and/or tabs have no means of holding the gasket in place at least on my combination. I went back to the M/P cast ones I have ran for years with no problems. I also have studs with nuts instead of bolts to hold the valve cover in place as it makes gasket placement easier upon removal of the cover.