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Discussion Starter #1
Just thinking that with the flow numbers we've been hearing about the new LS7 heads how much of a gain we'll see from a set of 1 7/8" headers on this engine. I'm betting that it will be pretty significant, at least 30-35 rwhp. :yeadog:

Anyone else willing to venture a guess?

Don
 

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from pictures I have seen it appears the factory set-up is close to a "shorty header" which is then connected to what appears to be "high flow" catalytic converter (does not look like 02-04 ZO6 cat) and remainder of exhaust system is 3 inch (?) to catback....if changing to longtube, then probably requires being catless (?) which means able to add a little timing - power (?).....regardless stock set-up is claimed by GM to be fairly efficient and may not give-up as much HP as C5 exhaust system ... however may get up to your 30rwhp increase becuase of removing cats and adding a little timing.....I sure hope so.
 

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The stock header looks better than any aftermarket system that I've seen. Large diameter tubing that is hydroformed to fit in a small space.

I haven't been able to see the interior of the first catalytic converter yet, but the header is basically taken care of. The only modification would be to port the area of welds near the collector.

ken
 

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I don't know Don. I think extensive work has gone into the stock manifolds. I don't think 30 hp would be possible but who knows.
 

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Discussion Starter #5
jub jub said:
I don't know Don. I think extensive work has gone into the stock manifolds. I don't think 30 hp would be possible but who knows.
John,

It was just speculation on my part. I guess we'll find out soon enough once a few brave souls offer their cars up for testing. :D

I just wonder why GM doesn't put a true tubular stainless steel header on this car and be done with it. I think we've all seen the headers that come as stock on the Viper, and they look damn good to me. :yeadog: Just thought the General would offer something like that as stock on the Z. :-?
 

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Don Benson said:
John,

It was just speculation on my part. I guess we'll find out soon enough once a few brave souls offer their cars up for testing. :D

I just wonder why GM doesn't put a true tubular stainless steel header on this car and be done with it. I think we've all seen the headers that come as stock on the Viper, and they look damn good to me. :yeadog: Just thought the General would offer something like that as stock on the Z. :-?
I think by using the cast iron manifolds, they are able to retain the heat in the exhaust manifolds and thus make the engine more fuel efficient and emissions friendly. At least that's the way I understand it.

I would like to see stainless headers as well but probably won't ever happen on a GM car.
 

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The cam timing is 211 intake, 230 exhaust. That should say something...the exhaust needing an extra 10% duration.

However, I believe it has been said that the ECU does not encourage tuning. More states won't allow you to use headers that move the cat further out. So what you can do may be more limited.

However, headers, a cam, and some tuning may yield very significant gains.
 

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well,

according to above picture they for sure don't look like cast iron. Also, they look like a good version of a shorty header. I think that a true long tube with a real collector(Burns)will help. The factory header also seems un-equal. Based on the the cam specs listed above, the exhaust can use a lot of help. The new intake, throttle body and C5R type heads probably define the exhaust defficienies more than ever. That would require a a cam with that much exhaust help. I would venture to say that this motor will see incredible gains with just a decent cam and set of good headers. GM left the easy shit to the average guy. Just a few bolt-ons and a cam and here is a 600 HP small blk.

Common sense tells you that 427 inches and 7100-7300 rpm is easily able to give 600-650 hp.

I would love to bet someone that we will see LGM or Cartek get 600-625 HP easily Cam and headers only.

Randy
 

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RandyN said:
I would love to bet someone that we will see LGM or Cartek get 600-625 HP easily Cam and headers only.

Randy
I love this Country.....
 

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RandyN said:
well,

according to above picture they for sure don't look like cast iron. Also, they look like a good version of a shorty header. I think that a true long tube with a real collector(Burns)will help. The factory header also seems un-equal. Based on the the cam specs listed above, the exhaust can use a lot of help. The new intake, throttle body and C5R type heads probably define the exhaust defficienies more than ever. That would require a a cam with that much exhaust help. I would venture to say that this motor will see incredible gains with just a decent cam and set of good headers. GM left the easy shit to the average guy. Just a few bolt-ons and a cam and here is a 600 HP small blk.

Common sense tells you that 427 inches and 7100-7300 rpm is easily able to give 600-650 hp.

I would love to bet someone that we will see LGM or Cartek get 600-625 HP easily Cam and headers only.

Randy


I am with you Randy.. :thumb:..a good set of long tubes, nice big cam, and a custom tune will do your numbers or close to it IMHO..GM always leaves a lot of HP on the table for drive ability, emissions, and fuel economy..modders are going to make this new motor rock.. :jammin:
 

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Not to be a a "I told you so", but the new manifolds are Stainless steel. Look at the new LS7 pics thread just started and you can see the print.

Randy
 

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RandyN said:
Not to be a a "I told you so", but the new manifolds are Stainless steel. Look at the new LS7 pics thread just started and you can see the print.

Randy
Ya beat me to the trigger... I was going to say the same thing. I was initially taken back by the caption in that pic. I thought my eyes were failing me. Stainless steel is good...
 

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The new C6 Z06 is producing at least 60 to 70 RWHP less than the than many/most members C5 with 427's. IMO the restriction is in the Headers and (about 20 to 30 HP) and the rest is in the camshaft. :cheers:
 

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The cam is a baby... .591 lift and 210 and 230 duration..LSA is probaby a real high number too for driveability...put a cam with duration in the mid 240's and well over .600 lift with LSA in the 110-112 range and get rid of that factory exhaust..they are nothing but shorty headers with cats on them..put on good set of long tubes with x pipe and a good flowing system, then get a good custom tune on it and watch that motor make some good HP and TQ..Chevy always leaves plenty of HP on the table :cheers:
 

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RandyN:

The header pic I posted here was taken from an engine display at last January's Detroit auto show...most likely the model was a wood/plastic prototype for display use.

Tony :z: :z:
 

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Not a prototype, it was the real thing. I've seen several of these on the cars that are rolling around bowling green and have a photo of the inner aspect of that header.

Although the tubes seem to taper near the collector they do not. They maintain the same volume but do change shape.

I think that the exhaust system for this car is done as is most of the rest of the car. Most of the mods made to the C6 Z06 will be cosmetic.
 

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Discussion Starter #19
Steve Tillman said:
The cam is a baby... .591 lift and 210 and 230 duration..LSA is probaby a real high number too for driveability...put a cam with duration in the mid 240's and well over .600 lift with LSA in the 110-112 range and get rid of that factory exhaust..they are nothing but shorty headers with cats on them..put on good set of long tubes with x pipe and a good flowing system, then get a good custom tune on it and watch that motor make some good HP and TQ..Chevy always leaves plenty of HP on the table :cheers:
Hmmm, can I get you to warranty it if I buy one from you and add those mods? :D

Don
 
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