Alright, I know I have read somewhere that some late model f-bodies may have ls6 blocks due to development of the Z06 and preparation for the engine. Does anyone know how to tell the LS1 from the LS6 block...(ie: where to look on the block and what number to look for) Sorry if this is a repost, I performed a search and there were no posts with the info.

 

According to GM, the sheer volume in which this block was produced meant that they were able to let some go over to the camaro and firebird program. It is said that 10-15percent of all 2001 F-cars and around 25 percent of all 2002 F-cars are running around with LS6 blocks!!
To confirm if your 2001-2002 F-body has an LS6 block grab a MIRROR and a FLASHLIGHT. Open the hood and head over to the driver's side to try and see the back of the left-hand deck, above the transmission flange. A cast-in 12561168 denotes the LS6 block