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Hi, I'm new here. Over at www.slantsix.com , we've had several discussions recently about the possibility of adapting the 2JZ head to a 225 Slant Six Chrysler block, since Japan based the design on it when building the inline 6 Toyota engines. I know the bolt pattern for the head bolts is 4" by 4.1", and the bore is almost identical. There would need to be much fabrication work done, but the basic question here is will the head bolt to the block? Other problems can be solved later.
 

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Heres the bigger question in my mind...if the toyota is indeed similar to the slant six and you are willing to swap on the head(which means you obviously are not afraid of having none "oem" chysler parts) why even bother just doing the head, swap the whole damn motor! You'll get a factory forged crank and rods and block that can 1000hp...if you just use the head, you'll need to use the intake too...so it wil look like a 2jzgte, why not use the 2jzgte bottom half too...this makes no practical sense to me, other than to say "hey, I was able to modify the supra head to fit on the slant six bottom end"...Now I have a head that can flow a 1000hp but a bottom end that can't take crap...You have way to much time on your hands..or your just way to into bench racing...
 
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Well, here are some reasons why swapping the whole motor will not do the intended job. Yes, it could be done, but the idea here is to build up the Slant Six engine.

1. All Slant Sixes from 1960-1976 had a forged crank and rods. '76 and up motors had a cast crank and different forged rods.

2. To participate in the Slant Six Points Racing series (bracket racing), there are not many rules, but you MUST use a Slant Six block.

3. Slant Sixes have already been built to run into the 10's in the 1/4 mile at 126 mph, but the head has always been the problem. The rest of the engine is strong enough to take more power.

4. Since the Supra head is a crossflow design and the Slant Six is not, custom headers will need to be fabricated for the Supra head, so at that point making a new intake is to be expected.

Does anyone have any photos of a Supra head, or measurements of the head bolt pattern? I should have specified that the 4.1" by 4" pattern is what Slant Sixes have.

This idea may not be the most practical, but it will fill the needs of a select market. Slant Six points races are starting to become more common at major races, at least in the east to midwest part of the country. Sponsors are putting up more and more prize money.
 

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Tim_K said:
Hi, I'm new here. Over at www.slantsix.com , we've had several discussions recently about the possibility of adapting the 2JZ head to a 225 Slant Six Chrysler block, since Japan based the design on it when building the inline 6 Toyota engines. I know the bolt pattern for the head bolts is 4" by 4.1", and the bore is almost identical. There would need to be much fabrication work done, but the basic question here is will the head bolt to the block? Other problems can be solved later.
I'd love to see any kind of articles that prove that Toyota based their 6s on american engines... that would be some interesting reading....

Any links?

My understanding was that the Toyota 6s are all based on the 2000GTs straight-6, which was designed with Yamaha... ?
 

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Toyota copied the 6 in the early land crushers from GM-they shared designs. If I was motived enough I could dig though my toyota books and find the paragraph that says it, but I wouldn't hold my breath. They, as far as I know, and have been taught, did not borrow anything from the preformance model inline 6's. The jz series was based on the 7m, which was based on the 6m,which was based on the 5m, which I bet you figure out the rest..
 
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Assuming the head has the basic correct dimensions, I think it will be a smaller job to adjust (weld up and redrill) the water jacket openings. And an external oil supply line can be run if needed.
 
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What is 96 by 94 mm? The head bolt pattern? If that's not too far off, the bolt holes could be relocated. It would be best to get an as-cast, unmachined head, if such a thing is possible. Any idea on the bore spacing? Slant Sixes are 3.98", except for between cylinders #3 and 4, which is 4".
 

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Yep that's the head bolt spacing. 96mm is the spacing of head bolts along the length of the block, 94 mm side to side. Can get bore spacing for you in a couple of days, but it should be 96 mm. All bores are evenly spaced. As you may gather head and block are separated by some miles!

Interesting concept but it does seem like a horrific amount of work. Have you had a head flowed yet? Will it actually be worth the effort?

Cheers Dave.
 
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