I'm looking for a new head. The plan is 1.7/1.44 over sized valves, and shaving it down for 9:1. I started with a '71 head and the machinist hit the water jacket while cutting for the hard seats. So I am wondering...

1) Is there any other improvements, other than the revised combustion chamber design in '68, that I should be looking for?

2) Would it be better to get a head that already has hard seats and resurface them for the larger valves or cut new seats altogether? Do you guys use the narrow "racing" style seats? I've heard they don't always seat well, but it seems like 1 way to ensure you don't hit water.

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'66 Dodge Dart

Anybody? Can i swap an 81 head on my 66 block?

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'66 Dodge Dart

Yes you can.

So far I've had a 1976 '600', a 1978 '447' head setup with new seats and porting and not hit the water jackets...My latest head to come back from the machinist is a 1981-ish head and he didn't hit water when putting in new seats. Not sure if the later heads have some improvement in this area or if I'm just lucky with the late heads I've picked (certainly doesn't work with the lottery).

-D.Idiot

I'm hoping to get lucky with an older head also. The problem is at the local yard there are 4 spark plug tube heads (not sure on which castings but most likely fairly early) and 1 hydraulic head (which it sounds will swap on to my solid lifter engine just fine?). So tomorrow I'll check castings for a spark plug tube head with hard seats or grab the hydraulic head.

Also, about this air injection port. No clue what it looks like or its exact function... will I be able to cap it off or something?

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'66 Dodge Dart

The air injection port is outboard of the #6 exhaust port on the manifold side of the head. It can be capped with a piece of flat steel stock with a hole drilled in in. It is an emissions addition.

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Casually looking for a Clifford hyperpak intake for cheap.

Very interesting Reed. Does the presence of the port (capped or not) provide a performance loss? Like I said, I don't really know anything about it or how it works. Do you mind explaining the system, just so I know how it works?

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'66 Dodge Dart

No real performance loss, it's a pain, as the system allows for the AIR pump to push air into the exhaust port bowls to clean up emissions (more oxygen means more burn after the spent charge leaves the cylinder. This port is also used on some models to feed the 'charge' tube which is similar to the EGR but some of the the spent gases are pumped to the air cleaner instead fo the intake manifold. If the head has the tube for the AIR or the charge tube, just take it with you, cut it off 1-2" from the head and roll it over and smash flat...that will plug the hole without having to go get some stock and making a plug.

-D.Idiot

The biggest complaint about the port is that the heads with the port weigh a little more than the heads without. Mopar made a plate that covers the hole in the head. You can find it on the exhaust manifolds of late 70s and 80s era 318 engines. It isn't on every one, but some 318 exhaust manifold have a plate bolted on the end that will fit the hole in the slant six head perfectly.

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Casually looking for a Clifford hyperpak intake for cheap.

Is it possible to braze the area your machinist hit? The interference fit for the seat is pretty tight. Combine that with a repair you should be ok.

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<img src="http://farm4.static.flickr.com/3173/2992308402_5481afb26e_t.jpg">

I don't think so, plus he cut into 4 cylinders... why he didn't stop after the first one baffles me.

So I'm off to the junkyard in a couple hours, any last minute suggestions on best heads (outside of the usual '68 and up suggestion)?

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'66 Dodge Dart

Ok so here is the update. I got an '81 head (casting 4095778) from a hydraulic slant. I'll need to go back tomorrow and pick up a valve cover since this one is trashed. I just want to make sure of two things before I'm off to the machinist...

1) This hydraulic head will work on a '66 block without modification other than covering the air injection port, correct?

2) Will the valve cover from any of the non-spark plug tube ('75 and up) heads work? Or do I need an '81 up valve cover?

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'66 Dodge Dart

(1) Yes

(2) You need the 81-up "square" valve cover

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Casually looking for a Clifford hyperpak intake for cheap.

Look for a different machine shop.

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'72 Duster 198 stock cam, 3:23's Hookers on jack stands for 8 years in the driveway
'79 Maxivan 360 Offy Qjet Comp RV cam/rusting in the driveway.
93 D350 160HP Cummins Auto Dually Clubcab needs a injector pump
2005 Golden Couch Buick

If you were closer to Tacoma I would give you a good core early 70s head and recommend that you take your head to Bud's Machine and Engine in Lakewood.

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Casually looking for a Clifford hyperpak intake for cheap.