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:


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.

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 ...

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Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

Now that I'm checking the pictures better I think the number is 4104362 ...

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Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

The casting number would indicate 1979 - 1980. Have a good one!

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66 Lil' Red Piggie Valiant (Mater Crusher) - Thanks Zilla!!!!! 72 Demon (Number 1 Son's)

That port in the rear is for the smog, (air), pump.

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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.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

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!!

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Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

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

Yep! That teardrop-shaped plug is the plug I mentioned.
Not if the plug is sealed up OK with a good gasket.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

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!!!

_________________
Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

If you are concern about leaks, tap-out the hole with a 3/8-NPT tap and install a pipe plug.
DD

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.

_________________
Martin Zappettini
1974 Dodge Polara RT 318cu.
1965 Valiant III Coronado Slant Six 6-Pack (soon!!)

All SL6 heads fron 1968 forward have the revised combustion chamber and yes, that design is better then the 60-67 design.
DD
http://www.slantsix.org/articles/combus ... hamber.htm