I am sure these have been shown before but as a relative newcomer to the scene I found it interesting seeing the difference between the new and old designs.
http://www.motoiq.com/magazine_arti...7-part-3-inside-the-gm-ls3-cylinder-head.aspx
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This sectioned head shows the LS3/L92 intake port contour. The port shape is derived from the Katech C6R ALMS car and improved upon by GM Powertrain. The intake port has a straight shot into the combustion chamber with a gradual radius in the critical short side of the port by the intake valve.
Here is an example of the LS3/L92 intake port on the left vs the older LS1/LS2 cathedral intake port on the right. Note how the LS3 port is wider and higher than the LS1 port.
Perhaps the greatest flow improvement in the LS3/L92 head is making the short side radius downturn more gradual with a straighter shot at the valve. This is something that head porters aim to do when modifying a head. You can see the LS3 head on the right has a much straighter shot at the valve in the area marked in red. A finer casting sand is used on the LS3 port cores and you can even see the difference in surface smoothness in the picture. Smoother means better flow.
Although a multi angle valve seat is something the Japanese have been doing for years, the LS3 is one of the first GM engines to use this flow improving trick. A wider valve bridge was needed to prevent cracking between the intake and exhaust valve seats.
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http://www.motoiq.com/magazine_arti...7-part-3-inside-the-gm-ls3-cylinder-head.aspx
<QOUTE>
This sectioned head shows the LS3/L92 intake port contour. The port shape is derived from the Katech C6R ALMS car and improved upon by GM Powertrain. The intake port has a straight shot into the combustion chamber with a gradual radius in the critical short side of the port by the intake valve.
Here is an example of the LS3/L92 intake port on the left vs the older LS1/LS2 cathedral intake port on the right. Note how the LS3 port is wider and higher than the LS1 port.
Perhaps the greatest flow improvement in the LS3/L92 head is making the short side radius downturn more gradual with a straighter shot at the valve. This is something that head porters aim to do when modifying a head. You can see the LS3 head on the right has a much straighter shot at the valve in the area marked in red. A finer casting sand is used on the LS3 port cores and you can even see the difference in surface smoothness in the picture. Smoother means better flow.
Although a multi angle valve seat is something the Japanese have been doing for years, the LS3 is one of the first GM engines to use this flow improving trick. A wider valve bridge was needed to prevent cracking between the intake and exhaust valve seats.
</QOUTE>