On a search I found one post that suggested the hole towards the front is possibly for a dip stick bracket for dip sticks that ran through the timing cover.  Mine takes a 7/16" coarse bolt which seems a bit big for a dip stick bracket.  Your threads may be different.

The hole in back is a blind hole on mine.  I replaced the pipe plug in the block drain hole with a 1/4" radiator drain cock since the regular pipe plugs seem to get stuck - at least for me - it always seems like the more I really need to drain the block, the more likely I'll round-over the plug.  On the crate motor I acquired from a failed project, I had to drill them out and use an easy-out to get them out of the block.

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Last edited by GPatrick (9/16/2013 9:43 PM)