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Yes, it has a car seat
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Discussion Starter #1
Has anybody checked whether the block in the GTO is really the LS6 casting or the LS1?
Dan
 

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761 Posts
Ok here goes, what is the diff between the ls1 and ls6? Diff blocks, heads? 50hp? Does "Gen3" refer to both these engines? Whats the "calloway C4B" engine that comes in the HSV GTS? Is it an ls1 or ls6or different again? (it has 400hp)

Adam
 

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The Callaway is a worked LS1. GM wouldn't sell the LS6 to Holden, so they went aftermarket. I guess Callaway might have info on their page. The Callaway is apparently not as nice, but never driven/been in one so can't say.
 

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Yes, it has a car seat
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1,884 Posts
Discussion Starter #4
As much as I can figure, originally the LS6 and LS1 were completely different. The difference in the block was in coolant flowing properties, not in configuration or general design. The LS6 came with different heads, intake and cam. In the later years of the f-bodies, a percentage of cars ended up with LS6 block castings instead of the LS1. Also for the last year or 2 of the f-body, the intake was changed on the LS1 to the LS6 intake. The information I've read online says that the GTO has the LS6 block (apparently they are only casting them at one place now, not both like they used to) and the LS6 intake. It still has the LS1 heads and cams (which many people say upgrading to aftermarket is better than going LS6 anyway). Also, it's the 'American' LS1 cam, apparently the Holden cam is different - but I haven't been able to verify this by anything concrete - just advertising stuff that they 'changed' the cam when turning the monaro into the GTO, but the cam spec's match the later corvette and f-body LS1's.

There's a casting number on the block to verify the block - but I'm not exactly sure where it is and you need a mirror and flashlight. It's also hot after you've run the engine. One of these days I'll check myself - I was just wondering about anybody else.
Dan

PS - please don't take anything I've written here as gospel and feel free to correct me if you know for sure I'm wrong about anything.
 

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...and former GTO owner.
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841 Posts

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13 year owner
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16,379 Posts
'91 beat me to it.
 

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13 year owner
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16,379 Posts
If it doesn't seem to have a brightness/shininess (yea I know it's a rough cast on the block, but you know what I mean), chances are, it may just be an LS6 block. You just need to verify it with the part number located on the drivers side engine block deck (just behind the rear of the head).
 

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Monaro - Australian for GTO
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80 Posts
Great info all. Just to get back to the original question, Has anyone verified if the block in their car is an LS1 block or an LS6 block?
My car isn't here yet so I can't look.
 

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13 year owner
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16,379 Posts
I have not.
 

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Just looked on the back of my block, my casting number is "12561168" which by another thread means i have an LS6 block. :cool: :cool:
 

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GTOWILL
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236 Posts
First off, please forgive my ignorance on this topic. I'm upgrade my B/R M6 with the best bolt-ons so as not to void my warranty (for now at least). However, an article (http://www.highperformancepontiac.com/features/0405pon_gtoautocross/) I read recently has me thinking about making some upgrades using GM Perofrmance parts. Since the GTO uses the LS6 block, what's everyone take on swapping the heads and cam for the LS6 counterparts? Would this void the warranty? Rumor has it that the '05 Autocross will have this configuration.

Be easy on me...I'm new to the group and the LS1 community.
 

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Registered Cruiser
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Just had a quick look through a thread on the topic on www.ls1.com.au and vehicles as far back as late 02 have the LS6 block and it has been used on all vehicles 03 - on.

Mick
 

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Yes, it has a car seat
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1,884 Posts
Discussion Starter #16
GTOWILL said:
First off, please forgive my ignorance on this topic. I'm upgrade my B/R M6 with the best bolt-ons so as not to void my warranty (for now at least). However, an article (http://www.highperformancepontiac.com/features/0405pon_gtoautocross/) I read recently has me thinking about making some upgrades using GM Perofrmance parts. Since the GTO uses the LS6 block, what's everyone take on swapping the heads and cam for the LS6 counterparts? Would this void the warranty? Rumor has it that the '05 Autocross will have this configuration.

Be easy on me...I'm new to the group and the LS1 community.
Well, as far as power goes - it appears there is much in the way of aftermarket heads and cams that will make more than an LS6 setup - probably for less money. Again, like any mod question the question is what is your goal for the car?
Now, as far as voiding the warranty - technically any mod has the potential to void a warranty - especially if they can prove it affected how the engine ran. It appears that much of the answer depends on what kind of dealership works on your car and your relationship with them. Now, if I were considering the LS6 H/C upgrade because I wanted to stay under warranty - I'd start calling some dealerships and asking them your question. You'd probably have to pay a bit more for them to do the work - but it's all a matter of your piece of mind. Personally I'm kind of glad they only put a 36k mile warranty because it keeps the price down and will cover actual manufacturing issues (ie. M6 problems) but when I'm ready to play - I'm not worrying about the warranty.
Dan
 

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Yes, it has a car seat
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1,884 Posts
Discussion Starter #17
JCMGTO said:
Just looked on the back of my block, my casting number is "12561168" which by another thread means i have an LS6 block. :cool: :cool:
Question - how did you manage to get to see this. I've dug around with the mirror back there for about 1/2 an hour and couldn't see any numbers on the back of the block. Is there a trick?
Dan
 

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13 year owner
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16,379 Posts
Dan, go to Sear’s and pick up one of those telescoping mirrors that you can angle. Shine a light back there, and you should be set. It shouldn’t be that hard on this car as half the engine isn’t hidden under the cowl like certain “other” cars.

GTOWILL, this has already been discussed to some extent. The LS6 heads and cam while improved over the LS1 counterparts are not up to par with what’s available on the aftermarket. I would consider the LS6 heads and cam a “low to mid-level” heads and cam setup compared to GTP, AFR, Patriot and a few others for heads and Comp Cams, Crane and a few other cams available. I would predict that if you elected to go the LS6 heads and cam route that your rear wheel hp would be in the 360-370 range maybe 380 if lucky and/or you have a particularly strong motor from the factory.

Conversely, with some of these aftermarker heads and cam setup for about the same price or CHEAPER, you can cross the 400 rear wheel HP mark, still be fully emissions compliant, and not suffer much in daily driveability.

That’s my $.02. I have nothing against the LS6 h/c setup, just that for the money spent, you can get better results elsewhere. If you’re a purist and want truly GM parts, then the LS6 setup may be your ticket.
 

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GTOWILL
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236 Posts
Appreciate the advice CMNTMXR57 and DANSLS1...looking forward to learning a lot from you guys!
 

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Yes, it has a car seat
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1,884 Posts
Discussion Starter #20
Take anything from CMNT over anything I say. He's done a lot more - I'm just an astute reader who waited a long time to get my car...
Dan
 
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