D

If you go back and look, I got the same thing on this head DD got on his. I find THAT more odd. lol

Now, as for the ports, those number might be proud just a tad. The manifold studs kept me from using the clear plate over the ports, so I had to rely on eye alone to judge when the ports were full. I'm sure the surface tension of the water threw it off a little. But it's close. Close enough for me anyway, because I don't really care. LOL The chamber volume was more critical, IMO and it's spot on.

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Rob

It is enough that Jesus died and that he died for me.

And it's not that the chamber is smaller. I actually never expected that to begin with. It's simply DIFFERENT.

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Rob

It is enough that Jesus died and that he died for me.

Right. Mopar wasn't trying to raise CR with this head, frankly, I'm not sure what they were thinkin'. The only -0- or near-zero deck OE engine was out of production for 8-9yrs, & the chambers aren'treally formed/shrouded in a way to create a ton of swirl....seems it was a predictably doomed abortion from it's inception. Lucky for those of us who find & put them to good use that they exist at all!

Yup and they weren't the only guilty party. Ford did the same thing with it's 400. That engine early on, because of its long stroke (4") had bad issues with detonation. It was actually one of Ford's best engines, but that problem plagued it its entire run from 70-82. But in Ford's infinite wisdom, they kept going shorter and shorter with the compression height on the pistons trying to lower compression and get away from detonation. All they had to do was put a two barrel version of the closed chamber Cleveland head on it and a dished piston with a quench pad on it and problem solved, but they never caught on. Quench knowledge and technology was just not known then. I'm like you. I have no idea what Chrysler's idea was, because to my knowledge, they never made a 225 with close to or zero deck height. I guess I get the chance to try what Chrysler should have.....although with a MUCH more radical camshaft. LOL

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Rob

It is enough that Jesus died and that he died for me.

Perhaps they had planned to use it with a set of dished pistons with a taller deck height, and wanted to ensure that an accidental mismatch of cylinder heads and short blocks from different years didn't accidentally wind up with a wildly inappropriate compression ratio?

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Matt Cramer
1966 Dodge Dart turbo / EFI project

What's wildly inappropriate about 10.2:1? That's what I'll end up with after I zero deck the block. Plenty of modern engines have that and higher. Of course, it won't run on pump gas without a pretty stout camshaft. But if they were still being produced, detonation would be handled through EFI computer programming similar to how it is now. I'm just having to handle it with hard parts instead of a computer. With the camshaft I am planning, DCR will be in the 7.9s. That's plenty low enough for pump gas. Probably be pretty efficient too.

Now my "for now" motor is a different story. I'm afraid I'm going to have problems with detonation "there". I'm seriously considering 86ing the severely milled head and using another one. That's money I really didn't want to spend, though.

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Rob

It is enough that Jesus died and that he died for me.

I would be interested in seeing how that head would work on a 170 (factory zero deck spec.) and a .022 shim gasket.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

"You really should read up on quench. I'm not going to argue the points with you because one, that was not my intent for this thread and two, this build was in no way a planned quench build. It's just turned out that way. If you want to continue to wrongly argue your quench theory, please start your own thread. Thanks. This was simply meant as an informative thread for finding something kinda cool."

It's never good to tell someone they're wrong and at the same time tell them you're not going to argue. That's a cop out.

I think MSM meant that as an OE head, Mopar may have intended to use a special piston to generate a -0- deck at the squish pad, and enough dish to have the same cyl.volume...thereby ensuring if somebody scrapyardf the new head it wouldn't jack the squeeze on say the '68 3/4 ton 4x4 . As far as modern engines goes, most of these are Al-U-minimum, 4-valve headed, & the cam timing is actually -0- overlap... Yet take a new 2.5L Hyundai 4cyl....192hp NA, & 13:1 squeeze. On pump regular...try that out!

I've actually thought about that. A lot.

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Rob

It is enough that Jesus died and that he died for me.

Crunching numbers on the 170, it would have a tic over 8.8:1, but having the quench pad, with the 170s "zero" deck height, it would clean up combustion a good bit, probably. With the stock or a mild little camshaft, it'd probably be pretty peppy. I don't think the block's actually "quite" zero deck, but zooming in on that would give it a little more quench and compression. They "should have" done that to the 170 from the factory, but made the chamber such to achieve a true 9.1 compression.

I agree with you Charlie. Unless you've been behind the wheel of a snappy 170, it's hard to convince people they can be quite as peppy as they are. In fact, if I'm the least bit disappointed with any of my 225 play, the 170s going back in it, because it' a ton of fun like it is now. But I don't think with 55 extra cubes the quench and extra compression in play from the zero deck height and the camshaft with the small four barrel that I'll be disappointed. I don't think I'll be disappointed even with my "for now" motor with the heavy cut head. My only regret would be detonation. With all the calculations I've made, it will have about 7.9 DCR so I think I'm safe. lol I'm havin fun and that's all that matters, right? Next time you're up, I should have a hot 225 in it and we can go for a cruise.

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Rob

It is enough that Jesus died and that he died for me.

I'll hold you to that

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

I have a uncut 170 block/engine in my garage right now. And it was definitely not a zero deck. I think it was about .060 below if memory serves me correct.

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Spec is zero, but I have never seen one at that number from the factory. Most of the ones I have checked have been between about .020 and .040.
Keeping the compression ratio up in the slant six was not a major concern for chrysler. I have seen CR for the slant listed, any where from 8.2-8.4 to one, but the specs did not change year to year. Every slant I have taken apart and measured (except one) was actually less then 8.0-1 CR.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225