Thread: Am I not seeing the obvious???

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I took the valve covers off of my 68 327 Chevy heads and I don't see any oil drain holes at the bottom corners. The drain holes are up at the sides above the valves. It appears that the valve covers are going to fill half way with oil before it drains back to the sump. Where are the bottom drain holes???

It appears that the valve covers are going to fill half way with oil before it drains back to the sump.


WAS THE OIL 1/2 WAY UP THE HEAD? if it was you got a problem, if you had been running the motor and there was no standing oil then it went somewhere. look a little closer.

This engine is a rebuilt and never been run. I probed around with a wire to see if there were drain holes that were plugged, and found no drain holes at the bottom corners. The drain holes I found were located at the sides between the rocker arm studs and the valves. I'm wondering if there are drain holes under the valve springs. The head # is 3911032. I can't find any pictures or info about this online.

There are not drain holes under the valve springs. The holes are in the front and rear corners of the heads, if I recall the holes are about 3/8" or so.

Again, There are NO holes in the front and rear corners. I've seen so many heads (Chevy's included) with drain holes in the front and rear corners and other places. These heads have two drain holes above the corners, higher than the valves. The drain holes are near the end head bolts of the middle row. Unless the engine is supposed to be tilted (rear end down), the valve covers are going to be half full of oil before it drains back to the oil pan. Should the engine be mounted in a tilt position???

Post some pics, mand u got everyone confused now!!! Maybe it was a bad day at chebbie and they forgot to drill them!!!!

What's the casting number on the heads?

Hey Tech, I was hoping you'd jump in here.

The head cast number is, '3911032'...

The block cast number is, '3914678'...

I tried to research it and all I got was more numbers, and no pics. The numbers tell me that it is a 68 307/327 block and heads. The heads may be Canadian, I don't think they're Camel back heads.

My biggest concern is those damn drain holes...They're up too high. If my engine sits level, then 2-3 qts of oil will pool in the valve covers above the valves...not good. That's why I asked if the engine can be tilted. That way only a 1/2 qt of oil will pool in the lower corner only.

EUREKA ! I FOUND THE ANSWER!!!!!

I made a long distance phone call to the Chevy div of GM and spoke with one of their techs. He had no idea about what I was talking about. He managed to switch me over to an old timer in another section. He and the other old timers had a good laugh at my question. He explained that I was not the only one to ask about that. In the 60's they got hundreds of calls from techs and mechanics wondering how GM got oil to flow uphill...

Get out your pens and pencils 'cause this ones for the books.

Title it..."OPTICAL ILLUSION"

If you stand beside the engine and look down at the head, it appears that the drain holes are on the sides, above the valves next to the rocker arm stud. It looks like the oil will have to flow upwards to the drain holes.


If you go to the front of the engine, squat down and look across the head long ways, you can plainly see that the face of the head is set higher and the drain holes are in a recessed area, well below the valves. The oil will run off the face of the head into the recessed area and down the holes.

Thanks guys for trying to help. I know that this one had you befuddled....Hell, I was sitting here with my left eye looking at my right eye for moral support. This is the first 327 I've worked with. I'm used to 283's and 350's.
I don't feel so dumb...this one stumped the techs and mechanics.