That hole is to allow the fuel pump pushrod to be installed prior to installing the pump. Once the pump is in place, put a pipe plug in the hole with a little brush-on gasket sealer, and gently snug it into place. I believe it's a 3/8" pipe plug. Don't overdo tightening it, it's a tapered thread.
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!