225 slant 6

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i would stay away from 1967 down motors because you stuck with only being able to run 1967 and down transmissions because of the small crank register and if you want a slip yoke drive shaft only 1966 and 1967 trans would give you that option, but with 1968 and up motors you can run alot more trans an even run the earlier trans but with a crank adapter.
 
So your saying the crank opening for the torque converter is a different size. And I've read that the '82 you cant bore over .030
 
You'll need to take into consideration that the later slants (76 and up I believe) have cast cranks.
 
RRR I believe you are correct, I think the block is lighter as well. I have never weighed them but, thought I read it a couple places. I wonder how many of us would ever push the limits of the later block or cast crank.
 
vitamindart said:
RRR I believe you are correct, I think the block is lighter as well. I have never weighed them but, thought I read it a couple places. I wonder how many of us would ever push the limits of the later block or cast crank.
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A well prepped cast crank can support 600 HP, so there's "THAT". LOL
 
And why..? It seems unless you're on some kind of certain mission to make little do more or just happened to have all kinds of extra parts and time.. so for me it's always back to the burning question "and why" wouldn't you spend the same money and get more?..
you should see my old threads where I wanted to make my 318 the world's fastest. Unfortunately it was more expensive than doing it 360...
The reason being more parts are made for it so it's more common and less expensive. just been my experience trying to make something faster...
 
For a turbo setup, I honestly wouldn't worry about boring it out .03 over. That's what boost is for. And on a 40 year hunk of cast iron, you want as much meat on the cylinder walls as you can get.
 
Pre 1975 is forged, post 1975 is cast. If you are worried about breaking stuff, go pre 1975.

Remember the \6 was developed when Chrysler built "bullet proof" engines.

Building a v8 is a simple as following a recipe. You can buy a 50 year book from SA Design that gives you that recipe and be as relevant today as back then. Building up a \6 actually requires you to think. The basics are the same, but they respond differently.
 
Consider this as well, the slant six was designed on blueprints as an aluminum engine. There were some made. So, imagine how much meat was designed into that engine to be aluminum. They did not change the casting process to thin the metal out when they switched to cast iron. So that means the cast iron is much thicker than it needs to be in the slant six. This can quickly be proven by how much the slant six heads can be milled. They can stand a .100" cut and not even flinch. Likewise, they can usually be bored .100 over. At least the 75 and prior. I don't know if they thinned them out after 75, but I wouldn't be surprised. I think the early engines with the steel cranks would be pretty much unbreakable as a turbo motor. That is to say, as long as it was prepped correctly.
 
The aluminium vs cast iron blocks is a nice myth. If you have every seen an aluminium block you would realize they are not the same molds. The cast iron block is so beefy, because that is how they designed them back in 1958.
 
kesteb said:
The aluminium vs cast iron blocks is a nice myth. If you have every seen an aluminium block you would realize they are not the same molds. The cast iron block is so beefy, because that is how they designed them back in 1958.
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Yes, now that you mention it, I believe you're right. That's just one of those things so easily parroted. I've seen lots of pictures of the aluminum blocks too so I should have known better.
 
Willyrd said:
For a turbo setup, I honestly wouldn't worry about boring it out .03 over. That's what boost is for. And on a 40 year hunk of cast iron, you want as much meat on the cylinder walls as you can get.
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The advantage to boring the cylinders out as much as possible is you can then de shroud the valves. Concerning how much you can over bore, I would always have the shop doing the work sonic check the cylinder walls, that is the only way to know. I recently had a last year 1987 slant block safely over bored .080 and it could have gone bigger, but that worked with the pistons that I wanted to use. If you need an big bore slant head gasket AussieSpeed has those.
 
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Ok I've got some cast numbers off the engines. One is 08176. 2463430-15.
Other is 09164. 2463430-17. And I have the 82 225 with a '82 904. I what to use a newer trans to do away with the cable shift. But I dont want to blow the engine up with. Turbo. Which way to go?
 
the block casting numbers, although ez to see are not the best way to trace back the pedigree of a slant six motor.
On an engine that had not had the combustion face of the deck milled, below the #1 sparkplug, kind of behind the alternator, there will be a series of letters and numbers stamped that will identify the day, month, year of engine assembly, the engine assembly plant, engine series.
There are online sites that will decode the stamping.
BYW, it is more than cast vs steel crank that will determine if your “turbo” slant six blows up. Read about the subject, attend a Slant Six drag race as a spectator, there you can talk face to face with folks that have actually put together a high performance slant six, get in the groove with the folks that know and I bet that you can build one to.
 
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RustyRatRod said:
Yes, now that you mention it, I believe you're right.
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No, he isn't—he's not answering the question that was asked, he's talking about the production aluminum Slant-6 engine, which, yes, differs to the iron block. In fact, the Slant-6 as it eventually wound up being produced in iron was originally designed for adequate rigidity and toughness if it had been made out of aluminum. This from "A History of Chrysler Corporation's Slant-Six Engine" by Willem Weertman, who was centrally involved in the design and development of the Slant-6 (Kesteb, did you work with him at that time? What other myths do you remember from back then?)

Here's part of page 19. Subsequent pages contain additional comments on the matter, such as "With the aluminum versions determining the major features of the design of the cylinder blocks, the cast iron block designs became straightforward with a closed top deck and full length water jacket."

Screen Shot 2019-11-04 at 19.02.09.jpg
 
Including the above post. Dan you need to read your previous post again. The aluminum block used a different set of blue prints, molds and casting process then the cast iron block. While the dimensions may be the same, the blocks themselves are designed differently.

The cast iron block is so beefy, because that is how they designed stuff back then. Also remember that over the years the block got lighter.

Ohh, in 1958, I was 1. So no, i don't know anymore myths. But one is enough.
 
kesteb said:
The cast iron block is so beefy, because that is how they designed stuff back then.
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No. The cast iron block is so beefy because it was originally engineered to be structurally adequate in either aluminum or iron. That is one fact we have directly from the mouth (pen) of the engineer in charge of the project. While nobody can dispute the significant differences between the aluminum block and the iron block, none of them bears on the bottom-end beefiness of the engine. The skirt depth is the same: adequate in aluminum, way more than adequate in iron—for one example. :)

You can be as info-resistant as you want, and you're welcome to believe whatever made-up nonsense you want to believe, but all it does is make you look like you're sitting there with your fingers in your ears and your hands over your eyes doing the equivalent of "La la la can't hear you don't see you la la la myth myth myth, it's beefy because things were beefy back then la la la". Me, I think I'll put more weight on "This is why we did it" from the guy who was in charge of doing it, than I'll put on "Kesteb said nuh-uh". :)

Also remember that over the years the block got lighter.
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That is both true and not relevant to the question at hand. :)
 
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slantsixdan said:
While nobody can dispute the significant differences between the aluminum block and the iron block, none of them bears on the bottom-end beefiness of the engine. The skirt depth is the same: adequate in aluminum, way more than adequate in iron—for one example.
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Dan, I'm not disputing what you said, but just adding an observation, and asking a question. The big blocks had a very similar skirt design, and had no thought of being made of aluminum. Also the aluminum and iron slant blocks had a totally different main bearing support.
Also, if as was stated, that one of the reasons for making an aluminum engine was to save money on machining, why not save money by taking metal out of the iron block
 
Charrlie_S said:
Dan, I'm not disputing what you said
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And I'm not disputing what you said—because you say stuff from a position of knowledge and curiosity.

The big blocks had a very similar skirt design, and had no thought of being made of aluminum.
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Yup, that's what makes it an unusually beefy design aspect on a low-output six-cylinder engine made of iron…but less unusually so on one made of aluminum. That observation is about as far as I can go; for more specifics you'd want to talk to Bill Weertman (who's still around) and ask him. I haven't; our conversations tend to centre around the Slant-6 for some strange reason.
:lol:

(Also, the forged cranks were used up through the middle of 1976 production, cast cranks after that. The big change for '75 was the cylinder head redesign.)
 
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j par said:
And why..? It seems unless you're on some kind of certain mission to make little do more or just happened to have all kinds of extra parts and time.. so for me it's always back to the burning question "and why" wouldn't you spend the same money and get more?..
you should see my old threads where I wanted to make my 318 the world's fastest. Unfortunately it was more expensive than doing it 360...
The reason being more parts are made for it so it's more common and less expensive. just been my experience trying to make something faster...
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I cant speak for the OP but I can tell you why I am building a slant six.

I'm tired of only seeing v8's and want to do something different. I want to go fast but not too fast, my car is gonna be 100% street so I am aiming for a 15 seconds. That's fun enough for the street but shouldn't get me into trouble.

And if I ever get bored with a 15 second car, I can pick up an Eaton m90 in ebay. That'd be different.
 
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