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| worth getting a head with air injection https://www.slantsix.org/forum/viewtopic.php?t=11834 |
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| Author: | gmader [ Mon Feb 21, 2005 1:24 pm ] |
| Post subject: | worth getting a head with air injection |
Hi all, I have an opportunity to get a head with the air injection casting stuff. It is casting number 3698447. Can the air junk be welded shut? Can it be ported? What are other people's experience with these heads. Greg |
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| Author: | Slant6Ram [ Mon Feb 21, 2005 1:51 pm ] |
| Post subject: | O.k. |
If you don't need the air injection system(in emissions states), there is no advantage to having an air injection head. It is a little heavier than the older head casting. No advantage there, but hardly a big deal. The injection ports can be plugged, but I don't believe welding is the suggested method. I know it's been explained several times, so do a search for blocking air injection. It's not a big deal blocking it. You will get hardened valve seats with any head new enough to have air injection, but it's only important if you won't be rebuilding the head. My ported head IS an air injection head, so I know you can still do porting. Don't pay extra for the head, but it should work just fine. |
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| Author: | SlantSixDan [ Mon Feb 21, 2005 1:51 pm ] |
| Post subject: | |
You can weld or otherwise plug off the air injection passages, but the extra cores in the casting mean these heads are heavier (about 20 pounds or so) and the extra passages limit the "meat" you can remove while porting. Also, the air injection causes the head to run hotter in use, so the metal may not be in as good a condition to start with. Me, I try to stick with the non-air-injection heads. |
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| Author: | gmader [ Mon Feb 21, 2005 2:39 pm ] |
| Post subject: | thanks |
Based on this, I will pass. Thanks for the advice. Greg |
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| Author: | Craig [ Mon Feb 21, 2005 5:14 pm ] |
| Post subject: | |
Quote: ......... but the extra cores in the casting mean these heads are heavier (about 20 pounds or so) and the extra passages limit the "meat" you can remove while porting. ........
20 pounds? I doubt it.
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| Author: | Dennis Weaver [ Mon Feb 21, 2005 5:59 pm ] |
| Post subject: | |
Are you certain it's an air-injection head? Reason I ask, the one I run on my Duster has the place at the back of the head for the air injection, bored out and bolt hole is drilled and tapped, but it is a solid hole. I spent many many hours porting this head and I am 100% certain there are no air injection ports. Not to say the one you're looking at will be the same, but if it's just a loose head, I'd look carefully first. D/W |
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| Author: | Craig [ Mon Feb 21, 2005 8:45 pm ] |
| Post subject: | |
Quote: Are you certain it's an air-injection head? Reason I ask, the one I run on my Duster has the place at the back of the head for the air injection, bored out and bolt hole is drilled and tapped, but it is a solid hole. I spent many many hours porting this head and I am 100% certain there are no air injection ports. Not to say the one you're looking at will be the same, but if it's just a loose head, I'd look carefully first.
Dennis (et al), D/W There was one of those heads on my '76 Valiant too. I believe these heads were testing out the new machining operation for the air injection or "pulse air" option. You will probably find some extra iron running the length of the head on the port side. This would have been drilled the full length of the head then small holes cross drilled from the exhaust ports into this long hole. Our heads (for the enigine!! ) do not have the long hole nor the cross holes drilled out. you can tell a head that has been drilled out by a metal soft plug in each end of the head. Now I do not understand why so many people here think they need to plug all those holes. Just plug the big hole in the back of the head. The little cross holes in the exhaust ports sometimes get full of carbon and are plugged anyway. |
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| Author: | kesteb [ Tue Feb 22, 2005 4:16 pm ] |
| Post subject: | |
I have several of the "peanut" heads. The '80 head weighs less then the others. No hard numbers, just the good ole grunt-o-meter. |
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| Author: | JohnnyDees [ Tue Feb 22, 2005 4:18 pm ] |
| Post subject: | |
I just finished an air head. Mine is only about 8 pounds heavier than my other two non air heads. |
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