243 LS6 heads
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From: Taxme, Ohio
243 LS6 heads I'm in the process of doing an LS6 H/C upgrade on my LS1. I put the 243 and 241 castings next to one another - No difference to the eye. Does anyone have information on the difference between these heads? Thanks.
intake ports
exhaust ports
deck side
241 - 243 castings
I inserted my fingers in the intake and exhaust ports to determine some internal differences. All I can say is with two fingers together I'm able to very slightly go deeper into the LS6 exhaust ports and with 3 fingers I "think" there's a tiny bit of volume increase for the 243s. It is difficult to believe that such a minuscule difference can add any significant power.
intake ports
exhaust ports
deck side
241 - 243 castings
I inserted my fingers in the intake and exhaust ports to determine some internal differences. All I can say is with two fingers together I'm able to very slightly go deeper into the LS6 exhaust ports and with 3 fingers I "think" there's a tiny bit of volume increase for the 243s. It is difficult to believe that such a minuscule difference can add any significant power.
It's not always size that matters. 
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
Originally Posted by SSpdDmon
It's not always size that matters.
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
Stock LS1 Heads
Chamber 66.67 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 200 cc 67 122 178 215 219 223 227
Exhaust 70 cc 52 97 133 156 170 176 180
Valve Diameter Intake 2.00"
Valve Diameter Exhaust 1.55"
Part Number 12559853 (1997-98)
12559853 (1999-00)
12564241 (2001-03)
Stock LS6 Heads
Chamber 64.45 cc 0.100 0.200 0.300 0.400 0.500 0.550 0.600
Intake 210 cc 62 126 184 224 251 256 257
Exhaust 75 cc 57 108 143 163 176 180 183
Valve Diameter Intake 2.00"
Valve Diameter Exhaust 1.55"
Part Number 12564243 (2001 +Z06)
I'd suggest you take the valves out and look into the runners from the other side, but I don't think you'd see the differences there either.
This is the way that people get ripped off when buying a set of ported heads- they simply don't know what they're looking at.
Ben T.
This is the way that people get ripped off when buying a set of ported heads- they simply don't know what they're looking at.
Ben T.
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12 Second Club
Joined: Mar 2005
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From: Corpus Christi
Originally Posted by jlashley2001ss
where is cheapest place to get the 243 heads?
some noted difference:
in port vol. ex port vol. ComChambr (cc)
+ gasket vol.
241---- 200 70 66.67
243---- 210 75 64.45
LS6 heads have higher flowing ports and chambers compared to LS1.
Last edited by cowboysfan; May 5, 2007 at 05:30 AM.
Thread Starter
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Joined: Oct 2005
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From: Taxme, Ohio
Originally Posted by SSpdDmon
It's not always size that matters.
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
Yes the LS6 heads are slightly bigger. They are also a different design. The D-shaped exhaust ports are said to be a big improvement over the LS1's O-shaped exhaust ports. I don't know all of the details. But when it comes to heads, bigger isn't always better.
I'm counting on those subtle differences to make more power but I am amazed at how close the two heads are. Even little things like where the side of a cutter rubbed along the intake port walls to cut the bolt head counter bores are identical between the heads. I think after seeing them together I might have opted to just have the 241 heads reworked instead of replacing them with the 243s. Although the deal on the new heads and cam was terrific.
12 Second Club
Joined: Mar 2005
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From: Corpus Christi
Originally Posted by cowboysfan
I got mine from Patriot Performance. try searching sponsors>>>>>>>>>>>>>
some noted difference:
in port vol. / ex port vol. / ComChambr (cc)
+ gasket vol.
241---- 200 / 70 / 66.67
243---- 210 / 75 / 64.45
LS6 heads have higher flowing ports and chambers compared to LS1.
some noted difference:
in port vol. / ex port vol. / ComChambr (cc)
+ gasket vol.
241---- 200 / 70 / 66.67
243---- 210 / 75 / 64.45
LS6 heads have higher flowing ports and chambers compared to LS1.
There are a few differences in the 241 to the 243 castings. The injector placement was revised for the 243 castings. You'll notice the 241 castings have a really tight SSR and a fairly low/flat floor in comparison to the 243's which is the main advantage.
Marty
Marty
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From: Taxme, Ohio
Originally Posted by Mr.MartyStone
There are a few differences in the 241 to the 243 castings. The injector placement was revised for the 243 castings. You'll notice the 241 castings have a really tight SSR and a fairly low/flat floor in comparison to the 243's which is the main advantage.
Marty
Marty
It's the short side radius. Search for a diagram for this.
It's much "improved" on the LS6- well, it's more simlar to an LT1 head. I'm not sure if it's "better" or not though. It's taller, but most importantly it's wider. You end up with more area at that cross section.
Ben T.
It's much "improved" on the LS6- well, it's more simlar to an LT1 head. I'm not sure if it's "better" or not though. It's taller, but most importantly it's wider. You end up with more area at that cross section.
Ben T.
Originally Posted by PREDATOR-Z
Maybe i'm missing what you're saying but the 243s are a direct swap as far as intake and injectors 
http://www.idavette.net/hib/ls6/imag...ges/407B_8.jpg
Hopefully that link still works. All I get out here is red X's for flipping everything. Stupid military firewalls
Marty
