Cathedral or Rectangular Port heads on 6.0
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From: Cape Girardeau, Missouri
GM High-Tech magazine had a great write up comparing them about 2 issues ago. The general conclusion I came away with is that they are really about equal. Im sure with more extreme applications there can be pros and cons to both.
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From: BFE
That cannot be further from the truth. While rectangular might show big numbers on a dyno, their performance is generally less than stellar (unless you are a true bench racer). Myself I would stick with cathedral properly ported 243/799s.
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It would be more of an issue with LS3 heads because they have a much larger valve. LS3 heads have great flow numbers but they come from a large valve and a large runner. This kills low end port velocity so I would try and keep that in mind. Also, they have a large chamber so compression is harder to come by with them.
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From: Marengo, Ia
LS3 heads and hears why,ls2 l92 heads makes 460rwhp 446rwtq. Over 450Hp, and a fairly broad and flat torque curve with a mid sized cam, and a set of heads that you can assemble with good springs for about $1000.
2004 and earlier LQ4/LQ9 blocks had long and short bolts while the 2005 and up had one length. You gotta make sure you get the right bolts for the year of your block. In this respect, it really doesn't matter what head you use, it's the block that determines which bolt set to buy.
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From: PA/MD
2004 and earlier LQ4/LQ9 blocks had long and short bolts while the 2005 and up had one length. You gotta make sure you get the right bolts for the year of your block. In this respect, it really doesn't matter what head you use, it's the block that determines which bolt set to buy.
Actually they switched mid year 04, some have the same length bolts, some have the short/long combo.......I've had two 04 block and one had the early pattern, one had the late pattern
LS3 heads and hears why,ls2 l92 heads makes 460rwhp 446rwtq. Over 450Hp, and a fairly broad and flat torque curve with a mid sized cam, and a set of heads that you can assemble with good springs for about $1000.
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From: Marengo, Ia
But you also have to consider that that 460hp was with a stock MAF with screen, a stock unported LS3 intake, a catted y-pipe, and a GMMG cat back. With a 85mm MAF or SD tune, a FAST 102, and an ORY with a cut-out I think 500hp could easily have been reached. Heck you could skip the FAST and just have the LS3 intake ported and you might still hit 500hp. I'd also like to see were you can get a set of 241's ported and dual springs installed for under $1000. Plus I think you need to find a pretty number happy dyno to hit 460hp with a 22x cam and 241 heads.
But you also have to consider that that 460hp was with a stock MAF with screen, a stock unported LS3 intake, a catted y-pipe, and a GMMG cat back. With a 85mm MAF or SD tune, a FAST 102, and an ORY with a cut-out I think 500hp could easily have been reached. Heck you could skip the FAST and just have the LS3 intake ported and you might still hit 500hp. I'd also like to see were you can get a set of 241's ported and dual springs installed for under $1000. Plus I think you need to find a pretty number happy dyno to hit 460hp with a 22x cam and 241 heads.
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From: Marengo, Ia
Okay, I'm having a hard time believing that 450rwhp can be made with 241's with bigger valves, bowl work, and a 22x cam. As far as the cost of a LS3 head swap, stock LS3 heads,rocker stands, offset intake rockers, and PRC .650" dual valve springs cost $1128.57, and I've seen several LS3 intakes with fuel rails and injectors for $300-350 on Ebay. Thats cheaper than most aftermarket heads that are capable of supporting over 500hp with a midsize cam.