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Help me to identify this head!!!
https://www.slantsix.org/forum/viewtopic.php?t=38317		 Page 1 of 1
Author:  Polara1974 [ Tue Dec 15, 2009 5:38 am ]
Post subject:  Help me to identify this head!!!
Hi all,
I have found this /6 head, I'm pretty sure that you will find this pretty familiar, but for me is the first time I see a head like this one.

Here are some quick pictures I just took for you to check:
ImageImageImageImageImage

The only casting number that i found so far is 4104352, it has the revised combustion chamber and no spark plug tubes.

One odd thing (for me) that I found is a hole on the back of the head, next to the #6 exhaust port, you can check it in this picture.
Image
In the picture is with the plug, if you remove it you will go directly into the water jacket.

I have the chance to use this head fo my next build-up, I know that the revised combustion chamber is better, but thatkeptr hole on the back, just keept me wondering.

Is this head better to play with than the old combustion chamber with spark plug tubes?

Can this plug be used to direct cooler water directly from the water pump into the rear of the head? Slant are well known for running much hotter on the back of the cylinder head.

Lots of questions!!! Is the fisrt time I see a head like this here ...
Author:  Polara1974 [ Tue Dec 15, 2009 5:42 am ]
Post subject: 
Now that I'm checking the pictures better I think the number is 4104362 ...
Author:  wvenable [ Tue Dec 15, 2009 6:12 am ]
Post subject: 
The casting number would indicate 1979 - 1980. Have a good one!
Author:  63Valiant [ Tue Dec 15, 2009 6:31 am ]
Post subject: 
That port in the rear is for the smog, (air), pump.
Author:  SlantSixDan [ Tue Dec 15, 2009 7:42 am ]
Post subject: 
The hole in the rear is for secondary air injection; an emission control technique that involves injecting air into the exhaust ports so that unburned fuel in the exhaust will finish burning. There's a blockoff plate available for this hole (at least up here), part number 3751 249 with gasket 4275 834.
Author:  Polara1974 [ Tue Dec 15, 2009 9:28 am ]
Post subject: 
Quote:
The hole in the rear is for secondary air injection; an emission control technique that involves injecting air into the exhaust ports so that unburned fuel in the exhaust will finish burning. There's a blockoff plate available for this hole (at least up here), part number 3751 249 with gasket 4275 834.
Isn't the plug in the head already? I remove the bolt took off the "teardrop" shape metal plug and there was the hole. Is this spot an easy leak for the exhaust?

So, in terms of performance this is an overall better head than the early ones with old chamber and spark plug tubes, right?

Thanks all for your answers!!
Author:  Doc [ Tue Dec 15, 2009 9:52 am ]
Post subject: 
The "peanut plug" heads are about 8 lbs heaver then the SP tube type heads.
The exhaust ports have more 'contours' in the bowl area under the valve so they take a little more porting work to get cleaned-up.

Over-all... the later heads flow about the same as the earlier versions.
DD
Author:  SlantSixDan [ Tue Dec 15, 2009 9:54 am ]
Post subject: 
Quote:
Isn't the plug in the head already? I remove the bolt took off the "teardrop" shape metal plug
Yep! That teardrop-shaped plug is the plug I mentioned.
Quote:
Is this spot an easy leak for the exhaust?
Not if the plug is sealed up OK with a good gasket.
Author:  Polara1974 [ Tue Dec 15, 2009 10:43 am ]
Post subject: 
I'll have to check if my Fel-Pro engine gasket set has the one for this plug.
I thought that it might be a place for leaks because it only has one bolt on one side, maybe with two bolts it will seal for sure.

One again, thanks!!!
Author:  Doc [ Tue Dec 15, 2009 11:19 am ]
Post subject: 
If you are concern about leaks, tap-out the hole with a 3/8-NPT tap and install a pipe plug.
DD
Author:  Polara1974 [ Tue Dec 15, 2009 12:45 pm ]
Post subject: 
Good idea!

Once again, is this the head to use for a performance modified Slant better than an early combustion chamber + spark plug tubes ones?
I think so, what do you think?

The combustion chamber seems better on the spark plug side on this one.
Author:  Doc [ Tue Dec 15, 2009 1:37 pm ]
Post subject: 
All SL6 heads fron 1968 forward have the revised combustion chamber and yes, that design is better then the 60-67 design.
DD
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