4 quarts of oil on the floor..huh?

[unclewill]

My first FE build, a 1968 side oiler service block. 
I've installed the engine in the car, almost ready to fire it up, priming the oiling system, drill is on high speed counterclockwise spin, 4 qts of oil pumped onto the floor in less than 30 seconds through a hole machined in the block drivers side rear! 
The hole is just outside the flange of my oil pan facing down.  I believe it's connected to the bypass valve in the back of the block.  My bypass valve is new.
What happened?  I'm assuming the drill on high spiked the oil pressure which opened the pressure bypass valve and shot oil out of the hole.  I'm assuming the hole should have a plug. 
Is this correct?  Any thoughts or advice on this problem?

[Posi67]

It needs a plug. Maybe someone can tell you the exact size but I'm thinking it was 1/4" pipe thread.

[blykins]

Needs to be plugged.....

I don't have a factory S/O block in front of me, but it's either 1/16 NPT or 1/8 NPT.  Pretty small. 

[unclewill]

I'm going to get a selection of plugs when I go to town to get more oil.  New garage floor too!  What a mess.

[Posi67]

Brent is likely correct.. it is a small plug and I don't know if I ever removed the one on my block. Luckily for you it isn't one inside the bellhousing.

The mess sounds familiar though. About 80 years ago when I was a kid and just changed the oil and filter in my car I dumped 7 quarts on the floor of my Dad's garage. The old filter gasket was stuck to the adapter and I put the new filter on without noticing. Exxon Valdez spill ensued. I've ALWAYS checked the gasket ever since. 

[unclewill]

Well thanks for the help guys, two lessons learned.

[428Marauder]

Did you press the "Realese Oil Slick" button?

Cause that would be cool, if your car had that capability.

[Qikbbstang]

In my teens my Mom called me in for lunch, came back out and added 5 cans of Valvoline Racing Oil to my 390GT which all ran out the oil pan hole with no bolt in it....ONLY did that once....

[shady]

oil filter gasket got me twice. both motorcraft filters. good thing I always start the motor & look under the vehicle for leaks.

[Barry_R]

Its a vertical passage that connects the bypass valve to the main galley.
Requires 1/8 NPT