Tell me about these holes

June 1, 2008 | By Richard Prince


Can you tell me what the two holes in the distributor side of the Chevy six-cylinder engine block are for? They are located between the draft tub and the fuel pump, about a quarter inch in size and they are unthreaded. One is on the pan flange the other is in the side of the block. Most six-cylinder Chevy engines have them.


I’m not sure but my best guesses are that they serve as locating points during the machining of the blocks when they are manufactured, or serve as mounts for accessories that are utilized only in some applications.

If any readers know more about these mysterious holes, please let us know.