Trans-dapt's Solid Rubber Oil Plugs fit 1.25" diameter valve cover holes. Also for use on many Chevy/GM car and truck applications. No grommet is required for installation.
 
Part # Product Media
9373 VALVE COVER "OIL" PLUG; 1-1/4" Hole; Chevy/GM Vehicles- RUBBER
Photo
$3.20
 
http://hedman.com/images/ePIM/original/9373.jpg