I have a bolt hole on the top of my 216 engine that I don't have a clue what should be in it. I found it as I was adding antifreeze. Any ideas?

http://s835.photobucket.com/albums/zz276/hdstickel/1953%20Chevy%20Engine/

thanks

Charlie


1953 5 Window
1994 Harley, Heritage Softail Classic
2006 Chevy Colarado
I didn't say it was your fault, I said I was blaming you.