mfrasca104

Hello all!

I have a 2002 Firehawk and I’m looking for an old magazine article Way back when my car was new I remember reading that GM had messed up and put the LS6 engine in some F-body's. There were distinct markings on the block. If anyone knows what I am talking about and could help me find that article it would be awesome.

Thanks

DrEvyl

iTrader: (5)

No, that is not true. Some 2002 LS1 cars got the LS6 block but not the actual LS6 engine, and it was quite intentional as they were phasing out the LS1 motor in favor of the LS2. There was not any realistic horsepower difference between the two. None of them got LS6 heads from the factory.

The way to tell if your block is an LS6 block is to look at the casting number at the top, back of the block and on the driver's side... the LS6 casting number is 12561168... anything else is the LS1 casting number.

demonspeed

iTrader: (7)

Don't forget the quicker way (although not as much of a guarantee as verifying part numbers) would be to just look for the "bullseye" marks on the front behind the waterpump/under the TB/in front of the valley on the top of the block.

This was the method GMHTP mentioned in that issue long, long ago. No bullseye = LS6 block (or, as many like to refer to it on here, "FLS6B").

DrEvyl

iTrader: (5)

I didn't know about the "bullseye" method... I remembered the part number thing and looked it up. Good info, though, thanks!

demonspeed

iTrader: (7)

An old timer like you did know? Come on...

DrEvyl

iTrader: (5)

Seriously. LOL The newest LSx car I've owned is a '99, so I never wondered about it.

RJDio

I just posted about this on a different thread. I'm looking at the article of interview with John Douro, GM Gen III, IV block staff engineer.
says about 10-15%of 2001's and 25% of 2002's have the LS6 block. Yes it was an improved design with 87% more ventilation, less pumping loss at higher RPM's. Tons of people have the LS6 block and don't even know it, something to chat about at car meets and such.

Here is some info about the "bullseye"; I've read that this is from the Canadian Montupet factory, which made LS1's. The lack of bullseye means your block was made in Nemak Mexico. Nemak was chosen to make LS6's because their process built stronger blocks, but you may have a LS1 without the bullseye, it just means your block was made in Mexico. Hope that helps.

I have the bullseye on my 2001 block, so 99.999% sure is a LS1 made in Canada since I don't believe they made LS6's. If you don't have the bullseye, good chance you have a LS6, check for #12561168. But no worries if you have the LS1, since engineers liked that manufacturing process better.

mfrasca104

Thanks for the Help. Good info.