what exactly is the purpose of sleeving a block??? is it risky ? will i benefit from it ?? oh Ya on an ls1

 

Before the LS2, it was the only way to get larger bores in the LS platform and stay aluminum.
1. Is it risky: Depends on who you ask. I've had my sleeved engine for long enuff to think it's not terribly risky if done right. Wet sleeves CAN have cooling issues. Dry sleeves CAN drop and result in catastrophe
2. Will you benefit from it: Yes. You will have increased cubic inches
3. Is it cost effective: It's not going to be the cheapest way to make power

 

The factory LS1 block is cast around cast iron sleeves, to safely go to a larger bore (significantly more than 3.905" or so) the factory sleeves are machined out and replaced with aftermarket parts, commonly going up to ~4.125" at which point you start to become limited by the factory 4.4" bore spacing which really cannot be altered. Sleeving LS1 blocks was common before the larger bore factory blocks (L92, LS7, etc.) and aftermarket blocks (C5R, warhawk, LSX, etc.) became available. Now it is rarely considered cost effective to sleeve a LS1 block for most people's purposes, now that these other options are available.