I agree with WYKOFF69Z, as long as it is one of the small bolts at the top. You only have oil slinging around in there not direct oil pressure. I would however do everything possible to get it out first, a punch can work as mentioned. If you have to drill it, straight and level is critical, if not you can do more damage than good, MUCH more. I would use a 90* drill, punch the center and drill slowly, if you can locate a left handed bit and a reversible drill you will be at a distinct advantage.