This subject came up quite a few years ago and I made a 3D model and posted it here showing how a sleeve could be designed to allow this and said Darton would make them.

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There's no such thing as too much cam....only not enough engine!

...And after Doug Dutra posted pics of stepped and milled/siamesed sleeves about 15 yrs ago...

Someone apparently actually tried it in real life, and posted here, with standard sleeves. Cannot recall the name/handle. Was about 5-8 yrs ago. I think Dennis is right it leaked.

Lou

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Home of Slant6-powered fun machines since 1988

A flanged sleeve is the best and better option. And with a step down where it protrudes into the main webbing area is probably even better with this large of an overbore. But it can be done successfully, though expensive for custom sleeves to be made...
I've built several exotic engines before including a Maserati Biturbo that uses this type of sleeves with figure 8 style copper gaskets that seal the water jacket on the water jacket floor where the step of the sleeve sits. A flange at the top just adds to give back rigidity to the deck and gives a strong seal top and bottom when you bore the entire original cylinder out of the block. Diesels also use a similar sleeve, especially if they are the wet style. So yes, for attempting such an extreme modification, a straight sleeve will never work, even if it didn't leak due to its lack of giving back any structural integrity from removing the entire original cylinder....

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There's no such thing as too much cam....only not enough engine!

Mike Jeffrey and Blaine Mueller.

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Official Cookie and Mater Tormentor.

Guy posted a video on a bike board I'm on of his buddy's turbo 292 Chevy at Fuel Tech for tuning.

https://youtu.be/oJ9w2Kx7h94?si=wTgYub96Fj2p4w6l

Pretty wicked.

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Official Cookie and Mater Tormentor.

That reminds me of Leighton and the Simca!
But he had the slant 6!

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http://www.youtube.com/hyperpack

Too bad he didn't have 4 digit horsepower.

I would love to see what a maximum effort Slant could do.

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Official Cookie and Mater Tormentor.

I do not know if that is possible at the bore size and spacing?

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http://www.youtube.com/hyperpack

That is Mike Staff from the Inliners forum that is making just over 1000 HP with a blown 292. He uses a Sissell aluminum 12 Port head that is identical to the head I took to the Slant 6 Awards Banquet get together about 8 or 10 years ago. Greg and Lou and a few others on here saw it. But his 292 truck is awesome for sure....

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There's no such thing as too much cam....only not enough engine!

[quote="Greg Ondayko" post_id=525877
I do not know if that is possible at the bore size and spacing?

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There's no such thing as too much cam....only not enough engine!

Over 1300 HP at @300 CI. is 4.33 hp/ci. That is amazing any way you look at it. If you could get even 3 hp/ci on a 238 " slant 6 you would be at 715 hp!

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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

Making horsepower is comparatively easy. Keeping parts together is the hard part.

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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

Apparently a big part of making that power with the 292 was putting more cam bearings in it to stiffen the cam. I was unaware they only used bearings at the front and back.

The things you put up with trying to make power with motors not designed to spin over 4500.

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Official Cookie and Mater Tormentor.

No, the 292 has 4 cam bearing journals not just 2. But he has added 3 more to stiffen the cam to minimize flex. The GMC Bonneville guys have been doing that for over 30 years. Those engines just have 4 mains just like the Slant, but the 292 has 7 mains....

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There's no such thing as too much cam....only not enough engine!

7 might help
But S happens

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Hyper_pak