The LS1 is a made for Aluminum
with Steel bore lining, which are in the casting moulds so the
finish produce you see the steel liner are
mould it with the block, the steel liner has ribs around it, to
prevent the liner from moving.
The size of the liner is 1/8 of a inch
(4/64 of and inch) before the cylinder is bore to the correct
size, so when the bore is at the correct size there is very little
steel left, only a hone and upgrade piston's of .010 thousand
of inch is the final recondition available.
The next option is to remove the liner
and and machine out the block to accommodated a larger liner,
the process is a secret in the production of this,
only 2 Company's like ARE and MTI know how to upgrade the LS1
with a new liner.
Here is so photo's of the block without been bored, so the liner
look big than the finish product, which is very thin in size.