And why is the chamber different from the 426 and the 5.7L?

The basic description of a hemispherical combustion chamber are there in the 5.7L. I like how the person writing the article never really came out and said why he didn't think it was a true Hemi head.

 

Actually he kind of does, if you read it closely, he says it is like a hemi with sections filled in. look closely around the outer edges, it is almost flat even with the piston top for a small section around both sides. Now compare it to the pic of the old 426, not even close to the same. The "hemi" as we have it today is more of a free form dished out chamber, much like many other modern cylinder head designs that aren't called "hemi."

You can get upset about me calling our new hemi a "hemi in name only," or you can accept that it is a far cry from the design of the 1960's. (which I should hope to hell it was 45 years later) But the fact is that there is very little that is "hemispherical" about the modern 5.7L hemi combustion chamber.

<edit> the difference being that 'hemispherical' implies half of a globe or sphere, which is about what the old hemi heads were. New ones are not.

 

I can see that area being a strengthening point since the old 426 Hemi head was iron where as the new 5.7L head is aluminum. it could also be there to increase compression.

just a though, but to me it still has the hemispherical properties as the old muscle hemi engines.

 

It is a Hemi, just updated. The reason the chambers were changed was because of the poor flame travel so common in the old style hemis. This is the reason for the poor emissions statement. As well, the head doesn't have to accomodate the piston above the deck, but the chambers again were modified to provide increased compression and flame travel.

I think the important thing here the valve placement within the chamber is the same, and unlike other engines out there.

It's not upsetting in the least. You're entitled to your opinion.

 

Looks like a hemi to me, albeit rather squished. So, what's the big to do? As I recall (I could go to the shop and look) my 392 heads are not "perfect hemi's," either.

As for the original 426 having iron heads, I worked for a small town racing Chrysler dealership (national record holding in SSAutomatic [as I recall] with a Dodge station wagon, our Plymouth coupes didn't hookup as well) in the mid-60's and though the very first race hemis did have iron heads, the aluminum heads were out right on their heals. I know this because I wasn't told the aluminum ones had come in and I grabbed one to move and about heaved it through the ceiling, not anticipating the lighter weight.

Hemis rule all the very highest performance piston venues to this day; just a fact of life.

All the best.

 

Gotta hate it when that happens.

 

I think there is possibly one other aspect we may be missing here too. That is the
feeling in the seat of your pants and the position of the petal down there on the right side that always seems to enjoy the thrill it gets when pushed to the floor[sm=gears.gif] I think out little smiley friend here says it all----DRIVE IT LIKE YOU STOLE IT!!

It just gives more meaning to the old saying "THERE NO REPLACEMENT FOR DISPLACEMENT"