Head comparision's

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02-04-2004, 12:20 AM

JZ'sTA

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Head comparision's

Okay I am sure this info is somewhere on this web site however I haven't found it yet.
I have a few different questions.
First, what is the difference between all the heads out there.
I see you have the 97-98 Corvette/F body heads that some say are the worst of the groupe. There is also the 99 and up LS1 heads.
Then you have 6.0 liter, 5.3 liter and 6.0 heads.
Seems like these are all nearly the same with a different compression.
I know the 6.0 are LQ9's and the 5.3's are LQ4's.The LS6 head is a LS6 head.
Same goes for the LS1 head. I see different heads being numbered like 53'cc or 77cc, what are the differences here and what head equals which number.
Also what is the compression differences between heads.
Lets just take a 2001 C5 stock makes x compression with ls1 heads. Add the 5.3 and the compression becomes ? add the LS6 heads and the compression becomes ??? or add the 6.0 and the compression becomes???
I am only looking for stock head vs stock head.
Hopefully this makes since to those reading as I didn't quite know how to ask the question.

Thanks

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02-04-2004, 01:17 AM

bigeller

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Quote:

Originally Posted by JZ'sTA

First, what is the difference between all the heads out there.

Differences are C/R, chamber size, port shape, and valve cover..

Quote:

Originally Posted by JZ'sTA

I see you have the 97-98 Corvette/F body heads that some say are the worst of the group.

They aren't really any worse.. They have the perimeter bolt valve covers and the coil packs are mounted directly to the valve cover and not the brackets like on '99 and up covers.

Quote:

Originally Posted by JZ'sTA

Seems like these are all nearly the same with a different compression. I know the 6.0 are LQ9's and the 5.3's are LQ4's.

Not excatly.. The LQ9 is the 6.0 HO with flat top pistons. The LQ4 is a low compression 6.0 with dished pistons. They share the same heads, both having 71.06cc chambers.. The 5.3 in it's most common form is the LM7. It also has dished pistons.. The 4.8 and the 5.3 share the same block and heads. I believe they're 61cc chambered.. The 4.8 is the LR4 and has flat top pistons.

Check info here:
http://www.gm.com/automotive/gmpower.../apps/vehicle/

Quote:

Originally Posted by JZ'sTA

The LS6 head is a LS6 head.
Same goes for the LS1 head. I see different heads being numbered like 53'cc or 77cc, what are the differences here and what head equals which number.
Also what is the compression differences between heads.
Lets just take a 2001 C5 stock makes x compression with ls1 heads. Add the 5.3 and the compression becomes ? add the LS6 heads and the compression becomes ??? or add the 6.0 and the compression becomes???
I am only looking for stock head vs stock head.
Hopefully this makes since to those reading as I didn't quite know how to ask the question.

The LS6 heads are approximately 64.5cc chambered and yield a 10.5:1 C/R.

The LS1 heads are approximately 66.67cc chambered abd yield a 10.1:1 C/R.

Given your example of the 2001 C5, the stock C/R is 10.1:1 with the stock #241 LS1 heads, 11.0:1 with the #862 4.8/5.3L heads, and 10.5:1 with the #243 LS6 heads. You won't want to add the #317 6.0L heads to a stock 3.898 bore. Your C/R would be low 9s.
Thanks[/QUOTE]