non-symmetrical hole in top of cylinder head

[justinowen]

'84 Monte Carlo 229 V6

Today I noticed a hole that stands out in the top of my driver's side cylinder head (under the oil filler cap).
Does this look normal?

It looks like the edges are a little jagged.
Is it an oil passage?

I was really concerned about it until saw this image from ebay (same cylinder head for sale):

Ebay links:

3.8L Vin K Cylinder Head for 81-84 Chevrolet Malibu | eBay

MALIBU 81-84 6-229 (3.8L). 3.8L VIN "K" CYLINDER HEAD ASSM. CAMARO 81 6-229 (3.8L). VIN specific computers. Used Late Model, Used Classic, New and Rebuilt. You must follow manufacturer’s guidelines for replacing your transmission.

www.ebay.com

https://web.archive.org/web/2025030...pid=5335822911&customid=&toolid=10001&mkevt=1

 

[ssn696]

That's the drain-back hole for oil that streams through the hollow pushrods to lube and cool the lifters and rocker arms. Sometimes racers will grind down the jagged casting flash to avoid bits breaking off under hard use, but if you don't plan to completely tear down to a bare head, you risk putting a piece of hard iron somewhere that could cause bigger problems than it might solve.

 

[justinowen]

That's the drain-back hole for oil that streams through the hollow pushrods to lube and cool the lifters and rocker arms. Sometimes racers will grind down the jagged casting flash to avoid bits breaking off under hard use, but if you don't plan to completely tear down to a bare head, you risk putting a piece of hard iron somewhere that could cause bigger problems than it might solve.

Thanks! You put my mind at ease. The fact that it was jagged and asymmetrical gave me pause.