If you use the stock ls rods, you will need to have them shaved 1mm total (.05mm on each side) off of the wrist pin end. This will allow the piston to have enough side to side movement. If you choose and aftermarket rod, such as eagle, they are a free flowing setup and clips would need to be incorperated into the piston to keep the wrist pin from moving. at that point you might as well buy forged pistons, such as je, arias, srp. They are designed for aftermarket rods, like the ones previously mentioned. Also with buying aftermarket pistons, you get a lighter, stronger product .and you can choose your compression.
matt