“Free power” is a term that is readily welcome in any mechanic’s dictionary. Unfortunately, if you own an LS2 powered vehicle the list of examples that fall into the free mods category are ridiculously limited. The easiest and cheapest way to step up performance is most definitely weight reduction, especially with heavier vehicles like the GTO and Trailblazer SS. Following closely behind in the spectrum of low-to-no cost modifications is intake manifold porting. Not only can you get a noticeable gain from the process, but it will keep your wallet intact as well.
If you’re at all familiar with what’s inside of your LS2, you know that the LS2 manifold is perhaps the most poorly designed piece of… art in the family of LS intakes. If not, a quick look at the manifold runners will show you exactly why we aren’t the intake’s biggest fans. Fortunately, all it takes to improve upon the stock design is a Dremel tool (a drill will do) with some grinding bits, a file (optional), a socket set, and a little bit of intake cleaner (also optional). From what we have gathered, if you do it correctly there have been reports of a ~20 RWHP gain before a tune. In theory, this process can be done to other plastic intakes as well, but it would be wise to do your research first to see if it’s worth it in your situation.
In this video, step-by-step directions are given to get the air flowing more smoothly upon entry to your engine. The elimination of turbulence in entering air will result in additional gains when combined with other modifications. From my personal experience, all work can be done in about a day and if you don’t already have the materials lying around the garage, they can be picked up for around twenty bucks. With the mess our economy is in right now, this modification is almost too good to be true, especially when a professional job can cost close to $200.