I'd recommend a drill press, or a Bridgeport mill if one's available. For one thing, the shavings you'll generate with the drilling and tapping don't belong anywhere near an assembled engine. I usually spot-face a flat spot on a curved surface with a small 4-flute end mill and low speed in a drill press before center punching and drilling. You don't want the drill bit to wander and break. Once the patch job is done, you can put the curves back in with a die grinder and a carbide burr.
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!