The simple, permanent fix would be to install some 1/4-20 studs about 3/4" long in the holes in the head with blue Loctite. They not only eliminate bottoming out another bolt and breaking it off, but they also give you guide pins to retain the gasket in the proper place as you install the cover. Filing or grinding them to the right length will also allow for the use of chrome acorn nuts if you decide to dress things up a bit.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!