New to building engines. Quick question.

I purchased a 350 sbc that came out of a 87 Vette. After bringing it home and tearing the whole thing apart I found this "hole." It just doesn't seem right to me, however there is a similar one tucked away on the outside of cylinder 7. Thanks for any replies.

http://i1381.photobucket.com/albums/...ps4fymmrry.jpg

if you are referring to the unmachined hole in the area at rear of valley-its oil drain back hole so oil can return to crankcase---at the front of block drains back to timing cover area thru 2 machined round holes which oils chain/gears