LS7 head flow numbers: 348 int/219 exh @.600 lift - LS1TECH



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LS7 head flow numbers: 348 int/219 exh @.600 lift

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Old 02-23-2005, 10:55 PM   #1
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Thumbs up LS7 head flow numbers: 348 int/219 exh @.600 lift

Check out this link. These numbers are almost exactly what is posted in the new issue of Corvette Fever. Incredible numbers. but they are flowed at 4.125 bore. I find it hard to believe any tuner can improve on these heads. Mike Chapman who is a revered head porter in the Mopar circles worked with GM on these. Judging by the tone of his post, I'm led to believe this is him or someone who access to this information.

http://www.gearchatter.com/viewtopic11202.php

They also have a pretty cool Gen III cam database of specs that is pages long. something *ahem* we could use here.
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Old 02-23-2005, 11:07 PM   #2
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Crazy numbers for GM castings out of the box. But I'm sure thay could be improved uopn. My 6.0l heads flow almost 30cfm more on the exhaust at .600 with a smaller 1.60 valve.
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Old 02-23-2005, 11:40 PM   #3
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Also notice how they peak at 359 cfm at .700 lift. This engine is begging for a big cam.
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Old 02-24-2005, 12:14 AM   #4
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Quote:
Originally Posted by 11 Bravo
Crazy numbers for GM castings out of the box. But I'm sure thay could be improved uopn. My 6.0l heads flow almost 30cfm more on the exhaust at .600 with a smaller 1.60 valve.
Was your exhaust flowed with a tube? Also if they're indeed c5r casting like i've heard them to be they still have a lot left. Porters have pulled 390-400 out of c5rs.

Last edited by stik6shift93; 02-24-2005 at 02:28 AM.
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Old 02-24-2005, 12:14 PM   #5
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Yea and it is only going to dyno 440 rwhp....I may be eating crow but I tell you this thing is underrated or the valve timing is incredibly tame. What would those heads and that cam do on a 346?
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Old 02-24-2005, 07:25 PM   #6
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not impressed with the 219 exhaust flow at all........most stg 3 heads get about 240+ (mine did).......intake numbers looks good though....
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Old 02-24-2005, 09:29 PM   #7
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Those numbers are great for a factory head, but are poor for a head
with a 2.2" intake valve.

My guess is they come up strong with porting, prolly near 300CFM@.4"
and 350CFM@.5"...
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Old 02-24-2005, 10:26 PM   #8
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Those numbers aren't very impressive at all for a 4.125" bore with a 2.20" intake and a 1.615" exhaust valve on a CNC'd head! My LPE CNC'd LS6 heads with 2.02"/1.57" valves flowed 301 CFM at 0.500" on a small bore versus the LS7's 315cfm on a large bore and my exhaust numbers were 218CFM at 0.500" vs 207cfm for the LS7. I hope the production LS7 heads are a heck of a lot better than that!!!
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Old 02-24-2005, 11:08 PM   #9
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Quote:
Originally Posted by John B
Those numbers aren't very impressive at all for a 4.125" bore with a 2.20" intake and a 1.615" exhaust valve on a CNC'd head! My LPE CNC'd LS6 heads with 2.02"/1.57" valves flowed 301 CFM at 0.500" on a small bore versus the LS7's 315cfm on a large bore and my exhaust numbers were 218CFM at 0.500" vs 207cfm for the LS7. I hope the production LS7 heads are a heck of a lot better than that!!!
Yeah, but what did they flow above .500? I doubt 348 cfm at .600 and they probably fell off after that. The LS7 heads just keeps going, where a ported LS1/LS6 head falls off. It's obvious this is going to be a high revving engine that will really wake up with a bigger cam and maybe some long tube headers with no cats.
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Old 02-24-2005, 11:53 PM   #10
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I wonder how big the runners are on these heads?
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Old 02-25-2005, 12:11 AM   #11
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Quote:
Originally Posted by texada
I wonder how big the runners are on these heads?
Yeah somebody give us the port volume!
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Old 02-25-2005, 05:45 PM   #12
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Quote:
Yeah, but what did they flow above .500? I doubt 348 cfm at .600 and they probably fell off after that. The LS7 heads just keeps going, where a ported LS1/LS6 head falls off. It's obvious this is going to be a high revving engine that will really wake up with a bigger cam and maybe some long tube headers with no cats.
For the amount of time that the motor spends above 0.500" lift, I'll take bigger numbers at this lift and below than this number and above any day of the week.
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Old 02-25-2005, 05:52 PM   #13
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Like I said, my guess is with porting 300CFM@.400" will be reality and 350CFM@.50"

400 or so will be in the .600" and greater. My guess is the meat is there to support it. Lets pray it is.

What happens is the 500HP that these things ship with, will become
head and cammed and exhausted 700HP cars.
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Old 02-25-2005, 06:03 PM   #14
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Quote:
Originally Posted by Big-DEN
My guess is the meat is there to support it. Lets pray it is.
I would agree. The reason for the offset intake rocker is to allow more material for CNC porting.

John - I agree about time spent at lower lift is where it's at for a street car. But for race or near race applications, these heads should open a whole new world for max effort cars. Time will tell.
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Old 04-04-2005, 08:48 PM   #15
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I know of a truck head flowing 399.5 on the same bore with the same size valve.
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Old 04-05-2005, 10:12 AM   #16
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The intake flow numbers are impressive for a factory out-of-the-box head, but those exhaust numbers are somewhat weak. Here is a flow sheet from my old Formula, just a set of MTI hand ported LS6 castings from over 2 years ago when I had the car.



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Old 04-06-2005, 12:54 AM   #17
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well tony i guess we know where the aftermarket will make a good bit of their money on these heads
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Old 04-06-2005, 07:07 AM   #18
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Quote:
Originally Posted by BrentB@TEA
I know of a truck head flowing 399.5 on the same bore with the same size valve.
no way

Matt
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Old 04-06-2005, 08:18 AM   #19
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Quote:
Originally Posted by DrkPhx
I would agree. The reason for the offset intake rocker is to allow more material for CNC porting.

John - I agree about time spent at lower lift is where it's at for a street car. But for race or near race applications, these heads should open a whole new world for max effort cars. Time will tell.

I'm trying to think of the articles and pics that I've seen thus far (which isn't working right now) but when you say the rocker is offset, is it also canted like a "semi hemi's" valve would be? (Not splayed like a big block but canted). I love the speculation here, but, we'll just have to play the wait and see game. More than likely these products will be scarce @ first and hella expensive.
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Old 04-06-2005, 08:42 AM   #20
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Quote:
Originally Posted by sb427f-car
I'm trying to think of the articles and pics that I've seen thus far (which isn't working right now) but when you say the rocker is offset, is it also canted like a "semi hemi's" valve would be? (Not splayed like a big block but canted).



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