Cylinder Head Testing - LS2 Dyno Thrash Part II: Head Shootout

As the name indicates, Livernois Motorsports throws the book at their Stage III LS2 cylinder head. Starting with a new set of LS2 heads, they run them through a five-axis CNC machine for port work that mimics their in-house hand port work. Fully assembled with Manley valves and Manley titanium retainers, this is a great example of what a good port job can do for an already outstanding factory head. With the better springs, these heads will work to .670-inches of lift, so you can put a very aggressive camshaft into the mix before you start to run out of valvespring.

On the flow bench, the Livernois LS2 head kept right up with the out-of-the-box aftermarket units, flowing in excess of 320 cfm at .600-inch lift. And that doesn't come at the expense of good low lift flow, so the torque and good street manners are still there.

On the engine, these heads are just as impressive. Running up to and over 540 hp, they help the LS2 exhibit a nice linear horsepower curve. Torque seems to start to suffer at 5,000-5,500 rpm, but that's right where the horsepower is in the power band.

Where these heads would shine is on a street racer's car that requires the stock look without giving away the obvious modification of an aftermarket logo on the end of the head. With this kind of performance from a stocker, you get a real good idea of just how amazing the stock LS2 head is to begin with. Unless you are building big inches or adding nitrous or forced induction, you may want to go through a couple of generations of modifications with your stock LS2 head at a good head shop before you fork over the big money for the aftermarket unit. On the other hand, if you are looking at making over 600 horses, go with one of the larger aftermarket pieces from the get go and don't look back.