You can go here www.moparchat.com then scroll down to & click on circle track chat & peruse Sanborns cooling mods(it'll take several hours)that are in a stickey at the top of the page which will work for BB & SB & will enable you to do this(extra cooling holes) mod(& better) to any block/heads.

live every 24 hour block of time like it's your last day on earth