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4.0 block compatability

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Canoe:
One of the frustrating things you'll find, is that there are varying opinions on what a Stroker is, or how to do it "right". So make sure you look at multiple writeups, and there are significantly more of those in the Jeep world.

If you'll be using that 4.0 head on a 4.0 block (with 4.2 crank and I think a cam that is not stock in either but made for strokers), then I'd expect/guess/assume that with a 4.0 head on a 4.0 block that it's a given that you'll need that coolant flow that was welded shut. And I'd expect you want to match the same shape & size too, and you may need to grind out all of the weld material that is up those passages, else the resulting turbulence could reduce flow. Do your research on polishing those passages, as sometimes a non-polished or specifically textured passage will have a higher fluid flow due to that textured/rougher surface holding a boundary layer of fluid, which resists fluid flow less than a polished surface that has a low or no boundary layer.
With the extra power/heat a stroker will be outputting, I wouldn't want to have reduced coolant flow. Look at a 4.0 block for the match to those triangular openings.

When I was looking at differences in the various 4.0 heads, I remember being surprised at needing different intake manifolds? I may not be remembering that correctly.

And there are differing opinions on which 4.2 crank is best or even works in a stroker. Early? Mid? Later? You'll have to confirm what that is about. And this is obviously the correct time to get your crank checked by a machine shop for true, etc.. Don't drop it!

I've not built a stroker, and it's been a number of years since I looked at doing so, so I can't give you my opinion of what is best... lol

BG SX4:
I found the answer here:
https://www.google.com/amp/s/www.jeepforum.com/forum/f8/4-0l-head-4-2l-block-water-jackets-explained-2647586/%3famp=1

The water jackets which have been plugged on the 4.0 head do not pass water through to the block on the 4.0 either. So a 4.0 head which has been plugged for a 4.2 block can be used on a 4.0 block as well.

Canoe:
With post after post and article after article talking about the necessity of closing off the water passages of a 4.0 head on a 4.2, I sure wasn't expecting that!


--- Quote ---there is no coolant passing through these water jackets from the head to the block. They may exist on the 4.0L head as well as the 4.0L block, but they serve one purpose and it was explained to me by Bennie Fulps of Hesco: they are holes that allow sand to escape when the block (and head) is cast. If you still are in doubt, look again at the head gasket for a 4.0L engine: there are no holes matching the water jackets that would allow passage of coolant from the head to the block.
--- End quote ---

wtf!
First image google gives me for 4.0 head gasket shows the gasket sitting on a 4.0 after the head is pulled. The gasket has triangular cutouts for those triangular openings in the head over the circular holes in the block.
Have I got this right? What am I missing?
dannix.net/lib/truck/jeep-engine-rebuild

Canoe:

--- Quote from: Canoe on September 25, 2020, 02:40:27 AM ---... wtf!
First image google gives me for 4.0 head gasket shows the gasket sitting on a 4.0 after the head is pulled. The gasket has triangular cutouts for those triangular openings in the head over the circular holes in the block.
Have I got this right? What am I missing?
--- End quote ---
I was missing that I was looking at the wrong side of the head...
Photo has the triangular openings already filled.
(Machinest is working on ending a tiny crack so it can't spread.)

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