drainage hole info

[zpyroro]

Anyone know where I can access the info on how to open up the drainage hole under my he plenum? There was a GM service bulletin years ago about this. Thanks

[Young1]

There is a bulletin to drill a 3/8 hole in the rear of the block in The Valley of the plenum. Why not use a drill bit, a stiff wire and an air blower to clear the oem tube? You have to pull the starter to do either anyway.