Anybody seen this little snippet from GM HTP magazine?

I know, I know, another post about the F-Body LS6 block. But it's in the Mag!

LS6 Block

 

Have you tried to get a mirror and flashlight in there? You need pencil-thin arms with triple wrists to get anywhere near the back of the block. I'm gonna try to see it from below sometime, I've got the dull casting without the bullseyes, so I'm fairly sure it is an LS6 block.

 

Yeah, I'm not going to go digging for the number. Using the old criteria, I'm satisfied that it is the LS6 block. I was hoping this recent article in the latest GM HTP magazine would provide more clear information- I didn't see the orginal article from a year ago so I don't know what information might have changed. But clearly, it's a sturdier block.

 

this article seems to be very missleading. from studying it i'd say that some may have a structurely stronger block but they still don't have an ls6 block under their hood from the factory as the ls6 block is still a different block than the ls1 (from my understanding). but all in all i find this very interesting.

 

I heard rumours that there were also LS1 blocks made by Nemak, so that'd mean that there were engines with the dull finish and no bullseyes that didn't have the change in breathing and bearing webs that marks out the LS6, but would have the stronger material. I decided to try to get a definite answer, so last night I was under the the car with a shaving mirror suspended on coathangers - there's no way to see it from above without an endoscope I think, and this is what I found - pic definitely a 12561168 block. I still don't know whether this block is machined as an LS6, which has tighter clearances, but according to Mahle, the LS6 and 2002 LS1 pistons are the same, so is there a difference in the blocks?

 

The way I read it is that GM used 2 suppliers for the block, Montupet, and Nemak. It states that Nemaks low pressure precision fan process has a 10% better matierial property, which would make Nemaks blocks stronger. This is why they used Nemak to make the LS-6 blocks. The diffrence would be in the bay to bay breathing charecteristics between the LS-1 and 6. The 6 came with a new "cast-in" design which dramatically increased ventelation by 87%. Some where optimistic that this made more HP, but no official documentation has been released. If you have a block with the 12561168, you have the LS-6 block. I found it easier to jack up the car and get under it with a flashlight to see the number. I saw mine plane as day in 2 minutes. For once I got lucky and got the 1168 block.

 

i may not have an ls6, mine being a '98

but i do have a z28

and it looks like a jet fighter minus wings....standing still

 

http://web.camaross.com/forums/showt...threadid=83912

 

Yeah, I took your advice and jacked it up. It took me more than 2 minutes to find it though:

LS6 Block Number