What is this open cavity in my 318 heads?

[67CBodyGuy]

What is this open cavity in the heads of my 318, and should I be concerned that it's not covered by a gasket or the intake manifold? (see area inside yellow circle)



It's a semi-circular cavity, about as wide as my pinky finger, no idea where it goes, what it's connected to if anything.

 

[RustyRatRod]

It's a heat sink. Normal.

 

[GTX JOHN]

No need to cover it.

 

[George Jets]

Yes heat relief, the hot exhaust gases flow through just below those openings.

☆☆☆☆☆

 

[Syleng1]

So it is also a special place that catches every small bolt/nut and “Jesus clips” that falls out of your hands while working on a carb.
Syleng1

 

[j_anderson]

So it is also a special place that catches every small bolt/nut and “Jesus clips” that falls out of your hands while working on a carb.
Syleng1

especially those tiny carburetor throttle pin spring clips... I managed to retrieve it but it took a mirror, a magnet, a pick and 3 days of patient fishing...

 

[C130 Chief]

Prevents a hot spot under the valve cover that can cause oil to coke. And as others have mentioned, a place for throttle rod clips to hide.

 

[ProjectBazza]

So it is also a special place that catches every small bolt/nut and “Jesus clips” that falls out of your hands while working on a carb.
Syleng1

Yup! Dropped a couple of both in there recently.

And just for the record: You can't use a magnet to get anything out of there, either.

Or at least none that I have.

 

[ProjectBazza]

especially those tiny carburetor throttle pin spring clips... I managed to retrieve it but it took a mirror, a magnet, a pick and 3 days of patient fishing...

Say what? You're more than skilled at it than I, that's for sure!

 

[j_anderson]

Say what? You're more than skilled at it than I, that's for sure!

I had a tiny magnet on the end of a short screwdriver. I couldn't get it to make contact and grab the spring directly but one fishing attempt got the magnet close enough to move the spring into a different position where I could then grab it with a hooked pick.

 

[H22A4]

It was an attempt by Chrysler to ‘shave some weight‘ for fuel economy purposes back in the day. Then they got serious a few years later with the Feather Duster/Dart Lite.