well the usual thread states "i didn't know the ls6 came in 02's?!?!" then u usually have everybody chime in and "yea but no gains over the ls1 whatsoever blah blah blah" u know the story. BUT....

Why wouldn't the ls6 have any gains over the ls1?

From my personal experience with my motor swap, and from several lsx books, the most important feature i thought the new ls6 block had, was the "improved cylinder to cylinder breathing". now, as most of you know, the better crank case ventilation you have, the more power you will yield(ex: vacum pumps for case). i'm not saying the ls6 block will make 10-12 more than the ls1, but wouldn't there be some gains? say 3-4 hp? i know from running different pcv/filter setups, you can usually tell a difference. whats your opinion?

 

I wouldnt say you would necessarily pick up power, but its a better oil circulating block. Kind of like the LS1 pump over the LS6. You dont gain power from it. Its just more effecient/effective pattern for circulation IMO.

 

you are both right ,plus ls6 block is stiffer.

 

How can you tell you have an ls6 block?

 

by checking the stamped numbers on the back

 

My thoughts exactly.

 

The bay windows is what may give you a gain in power. When the piston comes down, the air underneath the piston has to go somewhere, or else it compresses and becomes a pumping loss, soaking up power to compress that air which will offer no power in return. The bay windows allow that air to escape into other sections of the crankcase, where another piston may be moving upwards, needing that air so that it can move up the bore without pulling against a vacuum. It may not be a benefit realized by a 6000RPM 346ci engine, but higher RPM or even larger displacement engines may realize a gain.

You also have a larger oil crossover in the rear of the block from one oil galley to the other, just above the camshaft. LS6 blocks are also absent a certain casting, present in the valley on LS1 blocks, allowing an LS6 valley cover to be used. That casting has to be removed to use an LS6 valley cover on an LS1 block.

 

I meant any distinguishing marks that seperate it like difference in valley, or front or back of the block. I.E quick check when purchasing a motor.

 

I would like to know more also.

 

Read my post.

The bay windows, found on the LS6, not on the LS1:



The valley area of the LS1 (notice the casting "tower"):



The valley area of the LS6 (notice no casting):

 

Cool that is exactly what I needed to know, i bought an 02 shortblock or was told it was an 02, but looks like it probably isn't.

 

all 02 ls1's from fbodys have ls6 block?

 

If it's worth anything, I have two '02 motors. One is ls6 block, other isn't

 

Very cool thanks. What about if the engine is still in the car and with the intake installed?

 

LS6 block has this number cast on rear edge of LHS bank: 12561168.

With engine in car, this is real hard view, unless you remove the exhaust manifold/header.

 

this is what i meant by tunnels, not oil passages. i think it would make some power difference at any rpm range, it defanitly makes a difference at high rpm, bc its basically displacing 346 ci. inside the case(same bore,stroke). that turbulence and pressure has to go somewhere, and i believe these passages help.

 

Just an FYI guys, I just bought an LS1 A4 dropout two weeks ago. It came from a 2001. They gave me a copy of the title, which the last 8 digits of the VIN matched the last 8 digits laser etched on the block. And showing by the casted numbers you mentioned and the valley, its an LS6 block.

Maybe that's not groundbreaking to anyone, because I have read on here that there were a few 01s with the LS6 block. But its groundbreaking to me if its a better block.

One more thing, my PCV system was the same as the LS1s (even though my valley is the LS6 casting). So I'd assume the difference on the limited 01 and 02s that got the LS6 block is just the block, not the PCV system.

 

all which u stated is true badboy. some 01s(10%) and some 02s(15%) came w the ls6 blocks. i have a 01 also that had a ls6, also w the ls1 pcv. i havent compared my block number to my car vin, but i will have to. maybe there is a correlation?

but yes, i wouldnt call the performance gains "groundbreaking", but the fact that u were buyin a ls1 and ended up to a ls6. thats awsome. but overall, i am gonna have to go against the norm and say the ls6 will yield performance gains, and is alot better block in general!

 

After a spun bearing in my stock motor, I purchased a shortblock ls6...only to find out my stock block was in fact an ls6. I was never aware of the VIN method of confirmation. I'll have to remember that and check my buddies Z, which we've been suspiscious has an ls6 block in it.

 

I saw it on here before I knew about mine matching. If I had time to dig up the thread I'd post it. You should be able to search it out on here pretty easily.

Its on the driver's side rear of the block. Laser etched on a flat milled piece of the block. The last 8 numbers in the etch should match the last eight of your VIN. I was happy to see that mine did because that made me feel a little more confident in the mileage they advertised it at (mileage was on title, and title VIN matched block VIN).

Of course though, on a salvage title they can probably get away with any mileage they want.......which is why I was happy to see the LS6 block in mine......just made me a bit happier with the purchase considering the "unknowns".