Need help on a swap LS2 or ls6
 

I have a 2003 Chevy Silverado with a LS 5.3 Procharger and 4l80e trans ..Which of the two would work better for me.. LS6 out of a 2002 vette. The LS2 out of a 2008 SS trail... Hope one of these will work for me....Thanks Rick

i can't remember for sure if the 58tooth reluctors, knock sensor move, etc all started in 03 or not, but if so, the LS2 would be easier electrically. you'll also start out with more torque & have the bore to swap on the rectangle-port heads/intake with a 90mm TB.

Isn't a 2008-2009 engine 58x in the trailblazer? I think the 06-07 where the same engine that came in the 05-07 corvettes but just less power.

The LS6 from the corvette would be a drop in and go unit, everything would match up and be a easier install. Those cars still ran a P01/P59 computers that are 24x engines.