Pros Cons Using Truck Head or 5.7L Head
11-14-2001, 03:22 PM
#21
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by kewlbrz:
<strong>seems like the 6.0 liter head would be the ultimate for a forced induction package.
So let me understand:
GEN III has:
4.8/5.3 Truck Heads 64cc
5.7 LS1 Heads 68cc
5.7 LS6 Heads 68cc (raised intake runners and D port)
6.0 Truck Heads (2001+ Same as LS6 except for chamber size)
All heads above are same (valve angle, swirl characteristics etc...) except as noted?
Any that I am missing?
What is the chamber size for the 6.0L head?</strong><hr></blockquote>
Actually, 5.7 heads are 64-65cc. 5.3's are closer to 60cc I believe. 6.0 liter heads would be somewhere around 67-70 cc I believe.
[ November 14, 2001: Message edited by: 2quick4u ]</p>
<strong>seems like the 6.0 liter head would be the ultimate for a forced induction package.
So let me understand:
GEN III has:
4.8/5.3 Truck Heads 64cc
5.7 LS1 Heads 68cc
5.7 LS6 Heads 68cc (raised intake runners and D port)
6.0 Truck Heads (2001+ Same as LS6 except for chamber size)
All heads above are same (valve angle, swirl characteristics etc...) except as noted?
Any that I am missing?
What is the chamber size for the 6.0L head?</strong><hr></blockquote>
Actually, 5.7 heads are 64-65cc. 5.3's are closer to 60cc I believe. 6.0 liter heads would be somewhere around 67-70 cc I believe.
[ November 14, 2001: Message edited by: 2quick4u ]</p>
11-14-2001, 03:28 PM
#23
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by 2quick4u:
<strong>
Actually, 5.7 heads are 64-65cc. 5.3's are closer to 60cc I believe. 6.0 liter heads would be somewhere around 67-70 cc I believe.
[ November 14, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
according to www.mortec.com
they could be wrong ??
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99......350..........Gen.III, "LS1", aluminum, 68cc
12564241...01......350..........Gen.III, "LS1", aluminum, 68cc
<strong>
Actually, 5.7 heads are 64-65cc. 5.3's are closer to 60cc I believe. 6.0 liter heads would be somewhere around 67-70 cc I believe.
[ November 14, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
according to www.mortec.com
they could be wrong ??
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99......350..........Gen.III, "LS1", aluminum, 68cc
12564241...01......350..........Gen.III, "LS1", aluminum, 68cc
11-14-2001, 03:31 PM
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by vmoore:
<strong>Sporatic's dyno is about what the 5.3L heads are dyno'ing..</strong><hr></blockquote>
Vince, he had a very small B1 cam and NO PCM tuning. Besides, like I said before, peak hp numbers don't mean squat on a street car.
You are WAY too hung up on peak hp numbers IMO.
<strong>Sporatic's dyno is about what the 5.3L heads are dyno'ing..</strong><hr></blockquote>
Vince, he had a very small B1 cam and NO PCM tuning. Besides, like I said before, peak hp numbers don't mean squat on a street car.
You are WAY too hung up on peak hp numbers IMO.
11-14-2001, 03:32 PM
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by kewlbrz:
<strong>
according to www.mortec.com
they could be wrong ??
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99......350..........Gen.III, "LS1", aluminum, 68cc
12564241...01......350..........Gen.III, "LS1", aluminum, 68cc</strong><hr></blockquote>
That is wrong. 5.7, 64-65cc for untouched stock heads. That 68cc might be for ported but unmilled heads.
<strong>
according to www.mortec.com
they could be wrong ??
12558806...97-98...350..........Gen.III, "LS1", aluminum, 68cc
12559853...99......350..........Gen.III, "LS1", aluminum, 68cc
12564241...01......350..........Gen.III, "LS1", aluminum, 68cc</strong><hr></blockquote>
That is wrong. 5.7, 64-65cc for untouched stock heads. That 68cc might be for ported but unmilled heads.
11-14-2001, 03:35 PM
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]
I had GTP welded chamber heads from 1998/1999 and I could not use them with my new setup since my compression would have been thru the roof, 56cc chambers.
<hr></blockquote>
John, when you're doing the bottom end its very easy to spec a slightly shorter rod, or adjust the piston to lower the CR back down.
I had GTP welded chamber heads from 1998/1999 and I could not use them with my new setup since my compression would have been thru the roof, 56cc chambers.
<hr></blockquote>
John, when you're doing the bottom end its very easy to spec a slightly shorter rod, or adjust the piston to lower the CR back down.
11-14-2001, 03:39 PM
#27
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Re: Pros Cons Using Truck Head or 5.7L Head some tidbits I have dug up about LS6 heads:
"The LS6 aluminum cylinder head is cast with smaller pent-roof combustion chambers than the LS1 head. Compression ratio increases from 10.1:1 to 10.5:1, improving thermal efficiency and increasing horsepower."
"And the same exact heads are going to go in the 6.0-liter LQ9 for trucks. It says something about durability as well." --John Juriga, Total Integration Engineer, LS1/LS6 V8s"
"The LS6 aluminum cylinder head is cast with smaller pent-roof combustion chambers than the LS1 head. Compression ratio increases from 10.1:1 to 10.5:1, improving thermal efficiency and increasing horsepower."
"And the same exact heads are going to go in the 6.0-liter LQ9 for trucks. It says something about durability as well." --John Juriga, Total Integration Engineer, LS1/LS6 V8s"
11-14-2001, 03:43 PM
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Re: Pros Cons Using Truck Head or 5.7L Head True Terry, but then I would have been getting away from the popular Lunati 6.200 rods that they use in their stroker packages... I just traded teh heads in since I need to upsize the valves anyway, I went to 2.08/1.60's.
A number of strong nitrous cars run like 12-13:1 compression. But they are competition cars.
A number of strong nitrous cars run like 12-13:1 compression. But they are competition cars.
11-14-2001, 03:46 PM
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by kewlbrz:
<strong>some tidbits I have dug up about LS6 heads:
"The LS6 aluminum cylinder head is cast with smaller pent-roof combustion chambers than the LS1 head. Compression ratio increases from 10.1:1 to 10.5:1, improving thermal efficiency and increasing horsepower."
"And the same exact heads are going to go in the 6.0-liter LQ9 for trucks. It says something about durability as well." --John Juriga, Total Integration Engineer, LS1/LS6 V8s"</strong><hr></blockquote>
Yes they are the same EXCEPT that the LQ9 truck heads have about 4-5 cc more chamber volume to lower the compression back down on a 4" bore engine.
<strong>some tidbits I have dug up about LS6 heads:
"The LS6 aluminum cylinder head is cast with smaller pent-roof combustion chambers than the LS1 head. Compression ratio increases from 10.1:1 to 10.5:1, improving thermal efficiency and increasing horsepower."
"And the same exact heads are going to go in the 6.0-liter LQ9 for trucks. It says something about durability as well." --John Juriga, Total Integration Engineer, LS1/LS6 V8s"</strong><hr></blockquote>
Yes they are the same EXCEPT that the LQ9 truck heads have about 4-5 cc more chamber volume to lower the compression back down on a 4" bore engine.
11-14-2001, 03:53 PM
#31
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Re: Pros Cons Using Truck Head or 5.7L Head LS1 LS6 comparisons:
A vertical view of the same two intakes shows the LS6 (left) has a port that is taller at the entrance but wider in the mid-section, thus preserving cross-sectional area. The LS1 port
does not share that characteristic.
Side view cuts of the LS6 (left) and LS1 exhaust ports, again, show a smoother short-turn radius. On the piece at left you can also see some of the change to the combustion chamber. Note how the chamber wall in around the spark plug has been moved in, towards the valves and the roof has been lowered.
A vertical view of the same two intakes shows the LS6 (left) has a port that is taller at the entrance but wider in the mid-section, thus preserving cross-sectional area. The LS1 port
does not share that characteristic.
Side view cuts of the LS6 (left) and LS1 exhaust ports, again, show a smoother short-turn radius. On the piece at left you can also see some of the change to the combustion chamber. Note how the chamber wall in around the spark plug has been moved in, towards the valves and the roof has been lowered.
11-15-2001, 12:45 AM
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Re: Pros Cons Using Truck Head or 5.7L Head [quote]Originally posted by 2quick4u:
<strong>The only advantages of the 5.3 head is increased compression, availability, and cost. The increased compression may actually work against you on a daily driven street car.
Using the LS6 head or the 2001 and later LQ4 6.0 liter truck head would be better choices IMO. They have better flowing ports. The 6.0 truck head has the same ports as Ls6 but a slightly larger combustion chamber. This can be milled to maintain stock CR on a 346 or not milled for larger bore motors. If you are building an FI motor, you may want to go with them on a 346 to help reduce CR.
[ November 14, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
I agree 100%. I am using the 5.3l truck heads. I decided on those for the added compression they give (smaller combustion chambers compared to the 5.7l LS1 head). More compression is a good thing as long as you are not detonating. Make sure you have a lower temp thermostat, access to 93+ octane gas, and you are using a cam with quite a bit more overlap than stock. I am doing this and felt it was worth the gains. However, detonation kills motors REAL quickly, so be careful.
The 6.0l aluminum truck heads are an excellent choice as well. As stated above, the have the same porting as an LS6 heads, but with slightly larger combustion chambers than a production LS6 head. You can pick these up for around $450 shipped from Valvegod (valvegod@aol.com) compared to around $300 for the 5.3l heads. These are an excellent choice for larger displacement motors (i.e. larger bore), as they were designed to work with a 4.0" bore. The ports on the 6.0 heads are bigger, so velocity will suffer slightly compared to the 5.3l head, but they do offer a raised intake runner and a better shortside radius.
On my next motor, I might get Craig @ GTP to port a set of LS6/6.0 heads just to see how they work. Until then, I'll stick with my 5.3l heads. <img src="images/icons/smile.gif" border="0">
Jason
<strong>The only advantages of the 5.3 head is increased compression, availability, and cost. The increased compression may actually work against you on a daily driven street car.
Using the LS6 head or the 2001 and later LQ4 6.0 liter truck head would be better choices IMO. They have better flowing ports. The 6.0 truck head has the same ports as Ls6 but a slightly larger combustion chamber. This can be milled to maintain stock CR on a 346 or not milled for larger bore motors. If you are building an FI motor, you may want to go with them on a 346 to help reduce CR.
[ November 14, 2001: Message edited by: 2quick4u ]</strong><hr></blockquote>
I agree 100%. I am using the 5.3l truck heads. I decided on those for the added compression they give (smaller combustion chambers compared to the 5.7l LS1 head). More compression is a good thing as long as you are not detonating. Make sure you have a lower temp thermostat, access to 93+ octane gas, and you are using a cam with quite a bit more overlap than stock. I am doing this and felt it was worth the gains. However, detonation kills motors REAL quickly, so be careful.
The 6.0l aluminum truck heads are an excellent choice as well. As stated above, the have the same porting as an LS6 heads, but with slightly larger combustion chambers than a production LS6 head. You can pick these up for around $450 shipped from Valvegod (valvegod@aol.com) compared to around $300 for the 5.3l heads. These are an excellent choice for larger displacement motors (i.e. larger bore), as they were designed to work with a 4.0" bore. The ports on the 6.0 heads are bigger, so velocity will suffer slightly compared to the 5.3l head, but they do offer a raised intake runner and a better shortside radius.
On my next motor, I might get Craig @ GTP to port a set of LS6/6.0 heads just to see how they work. Until then, I'll stick with my 5.3l heads. <img src="images/icons/smile.gif" border="0">
Jason
