I hope that you can help. I was cleaning out the threads in my L26 block before I take it to the machine shop. I was going along nicely when I came to the front left head bolt hole. I put the tap in the hole just behind it instead, the tap handle was loose of course, and in fell the tap. I belive that this is part of the cooling system. I spun the block around a few times, tried to look up/down the hole with a flashlight, etc. Nothing. I was thinking about some sort of fiber optic light and some kind of long thin reacher. Any other suggestion or is the block history?

Knock the freeze plugs out of both sides of the block and look for the tap. Since you are taking it to a machine shop, if you can't find it or get it out, talk to the machine shop.