Help me understand heads differences - 5.3/5.7/6.0?
#1
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Help me understand heads differences - 5.3/5.7/6.0?
Hello all,
I'm looking SERIOUSLY at Absolute Speed's H/C deals, they are selling their 5.3 Stage II heads for 1449.00 right now plus refundable core charge, just seems too good to pass up!
Anyways, I'm relatively new to the H/C thing. Can someone give me a general overview of why one would go with 5.3L versus 5.7L versus 6.0L heads? I'm assuming it's mostly to either boost (5.3) or lessen (6.0) compression ratio, but that's probably not all?
The Absolute sale is on thru 4/1 for those interested BTW...Stage I starts at only 889.00, awesome deals.
I'm looking SERIOUSLY at Absolute Speed's H/C deals, they are selling their 5.3 Stage II heads for 1449.00 right now plus refundable core charge, just seems too good to pass up!
Anyways, I'm relatively new to the H/C thing. Can someone give me a general overview of why one would go with 5.3L versus 5.7L versus 6.0L heads? I'm assuming it's mostly to either boost (5.3) or lessen (6.0) compression ratio, but that's probably not all?
The Absolute sale is on thru 4/1 for those interested BTW...Stage I starts at only 889.00, awesome deals.
#5
TECH Enthusiast
Re: Help me understand heads differences - 5.3/5.7/6.0?
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by Pro Stock John:
<strong> 5.7= stock for us, 67 cc chambers
5.3= stock for truck, 62 cc chambers
6.0= stock for truck, 70 cc chambers
LS6= stock for Z06, 64 cc chambers.
Basically the 5.3's don't require major milling to achieve more compression... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">To elaborate on what John said, the 6.0L heads have similar flow numbers to LS6 heads, so if max flow is your aim and you don't want to spend the money on LS6 heads, 6.0L heads are a good compromise.
5.3L or 4.8L (theyre the same) heads have a smaller combustion chamber (as John said) which makes obtaining a higher compression ratio easier. I think that putting 5.3L heads unmilled on an otherwise stock 5.7L block, you get a CR of 10.5:1. You can mill them a little to easily get over 11:1 compression ratio without any serious piston to valve clearance problems.
5.3L heads have a smaller intake valve compared to the 5.7L heads, so you would definitely want to get new valves put in before installing them to your engine.
In the end, the 5.7L heads aren't bad by any means. With a .030" mill, you can obtain a 10.8:1 compression ratio, and with a good port, can come within 20-30 CFMs @ high lift of ported LS6/6.0L heads. And remember, CFMs aren't the only thing that makes a car fast...
<strong> 5.7= stock for us, 67 cc chambers
5.3= stock for truck, 62 cc chambers
6.0= stock for truck, 70 cc chambers
LS6= stock for Z06, 64 cc chambers.
Basically the 5.3's don't require major milling to achieve more compression... </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">To elaborate on what John said, the 6.0L heads have similar flow numbers to LS6 heads, so if max flow is your aim and you don't want to spend the money on LS6 heads, 6.0L heads are a good compromise.
5.3L or 4.8L (theyre the same) heads have a smaller combustion chamber (as John said) which makes obtaining a higher compression ratio easier. I think that putting 5.3L heads unmilled on an otherwise stock 5.7L block, you get a CR of 10.5:1. You can mill them a little to easily get over 11:1 compression ratio without any serious piston to valve clearance problems.
5.3L heads have a smaller intake valve compared to the 5.7L heads, so you would definitely want to get new valves put in before installing them to your engine.
In the end, the 5.7L heads aren't bad by any means. With a .030" mill, you can obtain a 10.8:1 compression ratio, and with a good port, can come within 20-30 CFMs @ high lift of ported LS6/6.0L heads. And remember, CFMs aren't the only thing that makes a car fast...
#6
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Re: Help me understand heads differences - 5.3/5.7/6.0?
In eveyones honest opinion which head offers the best CFM with good velocity. This is a very broad question and can be interpreted in many ways so any input will be appreciated.
#7
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Re: Help me understand heads differences - 5.3/5.7/6.0?
Im curious as well. Come on now, all these whiz-bang experts who've forgotten more about how to make big numbers than we'll ever know, give some low down here. Thanks in advance.
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#8
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Re: Help me understand heads differences - 5.3/5.7/6.0?
5.7= stock for us, 67 cc chambers
5.3= stock for truck, 62 cc chambers
6.0= stock for truck, 70 cc chambers
LS6= stock for Z06, 64 cc chambers.
Basically the 5.3's don't require major milling to achieve more compression...
5.3= stock for truck, 62 cc chambers
6.0= stock for truck, 70 cc chambers
LS6= stock for Z06, 64 cc chambers.
Basically the 5.3's don't require major milling to achieve more compression...
#9
LS1Tech Co-Founder
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Re: Help me understand heads differences - 5.3/5.7/6.0?
For what application, a stock bore motor?
In the end the LS6 heads will be the best if all the heads have the same porting and same size valves, and if we assume that none of them have been milled for additional compression. The feeling right now is that LS6 heads on a stock cube motor might be worth another 10rwhp.
In the end the LS6 heads will be the best if all the heads have the same porting and same size valves, and if we assume that none of them have been milled for additional compression. The feeling right now is that LS6 heads on a stock cube motor might be worth another 10rwhp.
#10
Re: Help me understand heads differences - 5.3/5.7/6.0?
1997+ LS1 66.67 cc 10.1 cr 2.00 intake 1.55 exhaust standard LS1 head and best all round
2001+ LS6 64.45 cc 10.5 cr 2.00 intake 1.55 exhaust d-ported version of the LS1
1999+ LR4,LM4, LM7 61.15cc 9.5cr 1.89 intake 1.55 exhaust 4.8/5.5 truck head small cc but also has small intake valve, needs head milling and valve upgrade
1999-2000 LQ4 (iron)71.06 cc 9.5 cr 2.00 intake 1.55 exhaust 6.0 truck engine good for boost but extremely heavy
2001+ LQ4 71.06 cc 9.4 cr 2.00 intake 1.55 exhaust 6.0 truck engine aluminum version good boost head
2002+ LQ9 71.06 cc 10.0 cr 2.00 intake 1.55 exhaust High performance version of 6.0 engine similar to LS6 best head for high boost applications
GMPP "Gen-III Racing" 65 cc 10.5 cr 2.00 intake 1.55 exhaust GM ported LS6 heads
GMPP "Showroom Stock Racing" 63 cc 10.8 cr 2.00 intake 1.55 exhaust stock LS1 head milled to reduce combustion chamber and raise cr
I hope this helps
2001+ LS6 64.45 cc 10.5 cr 2.00 intake 1.55 exhaust d-ported version of the LS1
1999+ LR4,LM4, LM7 61.15cc 9.5cr 1.89 intake 1.55 exhaust 4.8/5.5 truck head small cc but also has small intake valve, needs head milling and valve upgrade
1999-2000 LQ4 (iron)71.06 cc 9.5 cr 2.00 intake 1.55 exhaust 6.0 truck engine good for boost but extremely heavy
2001+ LQ4 71.06 cc 9.4 cr 2.00 intake 1.55 exhaust 6.0 truck engine aluminum version good boost head
2002+ LQ9 71.06 cc 10.0 cr 2.00 intake 1.55 exhaust High performance version of 6.0 engine similar to LS6 best head for high boost applications
GMPP "Gen-III Racing" 65 cc 10.5 cr 2.00 intake 1.55 exhaust GM ported LS6 heads
GMPP "Showroom Stock Racing" 63 cc 10.8 cr 2.00 intake 1.55 exhaust stock LS1 head milled to reduce combustion chamber and raise cr
I hope this helps
#11
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Re: Help me understand heads differences - 5.3/5.7/6.0?
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Originally posted by GoldRamAir:
<strong> 1997+ LS1 66.67 cc 10.1 cr 2.00 intake 1.55 exhaust standard LS1 head and best all round
2001+ LS6 64.45 cc 10.5 cr 2.00 intake 1.55 exhaust d-ported version of the LS1
1999+ LR4,LM4, LM7 61.15cc 9.5cr 1.89 intake 1.55 exhaust 4.8/5.5 truck head small cc but also has small intake valve, needs head milling and valve upgrade
1999-2000 LQ4 (iron)71.06 cc 9.5 cr 2.00 intake 1.55 exhaust 6.0 truck engine good for boost but extremely heavy
2001+ LQ4 71.06 cc 9.4 cr 2.00 intake 1.55 exhaust 6.0 truck engine aluminum version good boost head
2002+ LQ9 71.06 cc 10.0 cr 2.00 intake 1.55 exhaust High performance version of 6.0 engine similar to LS6 best head for high boost applications
GMPP "Gen-III Racing" 65 cc 10.5 cr 2.00 intake 1.55 exhaust GM ported LS6 heads
GMPP "Showroom Stock Racing" 63 cc 10.8 cr 2.00 intake 1.55 exhaust stock LS1 head milled to reduce combustion chamber and raise cr
I hope this helps </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Straight from GMHTP <img border="0" alt="[USA]" title="" src="graemlins/patriot.gif" /> lol
I was fixin to say GMHTP has an almost complete rundown of Gen III heads (it doesnt mention the aftermarket brands from LPE, MTI, ARE and so on) but it does list the differences between LQ9, LM7, LQ4, LS1 and LS6 heads. And is basically word for word what GoldRamAir said...
<strong> 1997+ LS1 66.67 cc 10.1 cr 2.00 intake 1.55 exhaust standard LS1 head and best all round
2001+ LS6 64.45 cc 10.5 cr 2.00 intake 1.55 exhaust d-ported version of the LS1
1999+ LR4,LM4, LM7 61.15cc 9.5cr 1.89 intake 1.55 exhaust 4.8/5.5 truck head small cc but also has small intake valve, needs head milling and valve upgrade
1999-2000 LQ4 (iron)71.06 cc 9.5 cr 2.00 intake 1.55 exhaust 6.0 truck engine good for boost but extremely heavy
2001+ LQ4 71.06 cc 9.4 cr 2.00 intake 1.55 exhaust 6.0 truck engine aluminum version good boost head
2002+ LQ9 71.06 cc 10.0 cr 2.00 intake 1.55 exhaust High performance version of 6.0 engine similar to LS6 best head for high boost applications
GMPP "Gen-III Racing" 65 cc 10.5 cr 2.00 intake 1.55 exhaust GM ported LS6 heads
GMPP "Showroom Stock Racing" 63 cc 10.8 cr 2.00 intake 1.55 exhaust stock LS1 head milled to reduce combustion chamber and raise cr
I hope this helps </strong></font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Straight from GMHTP <img border="0" alt="[USA]" title="" src="graemlins/patriot.gif" /> lol
I was fixin to say GMHTP has an almost complete rundown of Gen III heads (it doesnt mention the aftermarket brands from LPE, MTI, ARE and so on) but it does list the differences between LQ9, LM7, LQ4, LS1 and LS6 heads. And is basically word for word what GoldRamAir said...
#12
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Re: Help me understand heads differences - 5.3/5.7/6.0?
To make it short... If you are on a budget the 5.7 Ls1 heads are the way to go. Get them ported and your set...
If you have the extra money the LS6 are the best for performance. They offer the slightly smaller combustion chambers, for a slight CR increase, also the D shaped exhaust for improved flow.
The 5.3 are ok. These mainly if you want to increase CR without milling, they have smaller valves so you'd need a valve upgrade.
The 6.0 are good for blowers/turbos. The larger combustion chambers are good for the decrease in CR for blower/turbo use....
If you have the extra money the LS6 are the best for performance. They offer the slightly smaller combustion chambers, for a slight CR increase, also the D shaped exhaust for improved flow.
The 5.3 are ok. These mainly if you want to increase CR without milling, they have smaller valves so you'd need a valve upgrade.
The 6.0 are good for blowers/turbos. The larger combustion chambers are good for the decrease in CR for blower/turbo use....
#13
TECH Apprentice
Re: Help me understand heads differences - 5.3/5.7/6.0?
Has anybody modded the LS1 exhausts to D port configuration? Did they flow better? Also is it only the late LS6 heads that have the sodium valves or do the late 6.0 head get them as well?
I'd like truck heads with sodium valves.
I'd like truck heads with sodium valves.
#15
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Re: Help me understand heads differences - 5.3/5.7/6.0?
ss1le02 ...
It's not just high lift that causes piston to valve clearance problems, but duration is a very big factor. I understand that duration plays even a more important role. The 5.3 heads will allow for a larger cam than the 5.7 heads as long as both heads are setup to yield the same CR.
You say "milled" ... Well, it all depends on how much they are milled and the cams lift and cam duration.
There is no simple formula that I am aware of.
Ron,
It's not just high lift that causes piston to valve clearance problems, but duration is a very big factor. I understand that duration plays even a more important role. The 5.3 heads will allow for a larger cam than the 5.7 heads as long as both heads are setup to yield the same CR.
You say "milled" ... Well, it all depends on how much they are milled and the cams lift and cam duration.
There is no simple formula that I am aware of.
Ron,
#18
Re: Help me understand heads differences - 5.3/5.7/6.0?
I think even up to 11.0 CR you'd be fine running 93 octane pump gas....detonation should NOT be a prob with a proper tune.....
<small>[ April 14, 2003, 09:28 AM: Message edited by: SuperZ28 ]</small>
<small>[ April 14, 2003, 09:28 AM: Message edited by: SuperZ28 ]</small>