78 Van 318 going in 75 Duster head problem.

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jimfrazer

jimfrazer

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Restoring a 75 Duster with a dodge 318 from a 78 van 200. The head has a vent hole where the exhaust manafold attaches. Put a A body manafold on but it and it doesnt cover the small hole at the bottom. The van exhaust manafold covers the hole. What do I do? I am new to this and have no idea what the hole is there for if the old manafold coverd it. Have to use a 70s A body manafold to get past the steering box. any help would be greatly appreciated.
I looked it up online and could only find it on the NH Mopar heads 318 and 360. What is NH?

Thanks
 
this hole is below where the exhaust manifold sits? they are A.I.R. injection holes,part of emissions. you can tap them and put a set screw in but not sure what size? you could use a drill bit to find the diameter and then look at the charts to find which size to use. Bob
 
X2
Tap threads and install set screws or bolts and cut off the head. This is done all the time.
 
Those are A.I.R. injection ports. Run a tap through, and use Allen set screws with Loctite. I think 1/4"-20 fits .
 
May not be a bad thing at all. William is right, 1/4-20. But the ports are an attribute of 302 heads. May be worth checking the casting numbers to see what you've got. Also, it's a million times easier to plug those ports outside of the engine bay. Ask me how I know.
 
Thats another strange thing. The number is 43875303 and on the other side the numbers are 2-24-86. Is that the Manufacturoing date? Its out of a 78 Van. The guy died and so I dont know if he changed the heads when he put on the Edlebrock intake and 4bbl carb. I tried to blow compressed air and heard nothing. like the holes are clogged. Should I tap them anyway? I am using the old manafold from the van on the passenger side. so I only need to tap the one side. OR...tap them all now in case I get headers later since I have it out now.
 
OK they were just clogged. I will tap. The hole is 9 mm. So do I tap with a m8-1?
Thank you guys for clearing this up. I thought I was sunk.
 
Tap 1/4-20 like they said. You might even want to grind those pads down some while they are out. When I went to put my exhaust manifolds on, they hit on those pads and they were the only ones I could use on my car. Dennis
 
drill and tap them. I had the same issue the first time I swapped engines in my 69 Barracuda. I bought a set of cheap headers (before I knew all the issues with fitting them) and welded tabs on the bottom of the flange to cover the holes... ugly but it worked....
 
Thanks a bunch for all the help. Drilled, taped, and set screwed w/ locktite all the holes. Can I use a van exhaust manafold on the pass side and a stock duster manafold that goes over the steering box on the other side? The old duster one is a bit smaller than the other. Will that impeed the running of the engine?
 
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