Hole in the front of the cylinder head.

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Ahatchett

Ahatchett

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So the slant 6 in my 63 dart has a hole in the front of the head and I can't figure out what size freeze plug goes in it if it is a freeze plug. I believe the slant is out of an 83 Dodge d100. But I don't know for sure.
It's right behind a the hose to the head from the water pump.
These aren't my pictures, just the only one I could find with the hole visible online.

100_1285.jpg


IMG_20180306_012438.jpg
 
Visit your local parts house and buy a couple of various sizes, use the one that fits, and return the others.
 
Ahatchett said:
I got a kit to try that but there weren't any any that small.
Click to expand...
That ‘hole’ is a drilled passage that runs the length of the cylinder head and is cross drilled into the exhaust ports, that allowed fresh air to be pumped into the exhaust ports to help to clean up the exhaust emissions.
Should take a standard size cup plug, maybe 3/8 or 1/2.
The air in opening is to the rear side of the #6 intake port, it also should be capped or plugged,
 
No, sir. The one and only air injection port in air injection-equipped '72-up Slant-6 heads is at the rear, on the manifold mounting face, aft of the rearmost exhaust port.

'84 FPC shows a cup plug for the front hole, part № 5203 340. Crosses to a Dorman № 555067, specced as a 39/64" cup plug.
 
slantsixdan said:
No, sir. The one and only air injection port in air injection-equipped '72-up Slant-6 heads is at the rear, on the manifold mounting face, aft of the rearmost exhaust port.

'84 FPC shows a cup plug for the front hole, part № 5203 340. Crosses to a Dorman № 555067, specced as a 39/64" cup plug.
Click to expand...
Thank you, I'll stop by the auto parts store when I get a chance and let you know if it works.
 
"The one and only air injection port in air injection-equipped '72-up Slant-6 heads is at the rear, on the manifold mounting face, aft of the rearmost exhaust port."

yes, but how do you think the air injection hole at the rear face of the head connects to the exhaust ports?
the exhaust ports are connected to the air injection passage via a gun drilled passage that runs the length of the head. The cup plug that you identified closes the gun drilled passage and is the point at which the lengthwise drilling operation started.
 
Does driving it open hurt anything then? Because it's been parked for a couple months because of this.
 
Ahatchett said:
Does driving it open hurt anything then?
Click to expand...

start the motor and see if you can feel exhaust pulses at the hole,
(if you have a mechanical fan blowing it will be hard to tell,,,but I would expect if it was leaking exhaust gas there would also be traces of carbon / soot around the hole) if you do not, either
1) the passages have filled with carbon over time and have plugged
and / or
2) perhaps the head was rebuilt at some point in time and the small passages in the exhaust port that lead to the lengthwise passage were threaded and had a small allen screw threaded in, that is a common practice.

if you do feel exhaust pulses, or see carbon, you have a carbon monoxide leak under the hood of the car, you would want to address that.
 
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