We initially tossed the idea of comparing a stock LS1 with a conventional small-block 350, but after questioning the angle we later realized, what's the fun in that? And dare we say, it's already been done by others who'll be the first to admit that they did a fair job of updating you with the crucial differences-but certainly did little to stimulate the gearhead factor. To kick it up a notch, and satiate our hunger for power, we set the stage to bump up the cubic inches of a later-model LS2 into a big-inch 402 and pin it against a "warmed over" 406ci small-block.
Our requirements for this challenge: All components had to be readily available, over-the-counter production pieces; nothing over 11:1 compression; we had to use a hydraulic-roller camshaft; and we had to keep the components as close as possible, meaning we had to use the same manufacturer for our cylinder heads, camshafts, and manifolds, and most importantly, both bullets had to share the same carburetor.
Doesn't seem like that big a deal, right? Wrong. You need to take a closer look at the flow capacity of an LS cylinder head. Given the nature of its 15-degee valve angle over the conventional 23-degree cylinder head, we're talking race technology that's trickled down to the consumer level. By altering the angle of the valve, you create a much more direct path, which allows a greater volume of air to traverse into the combustion chamber at a faster rate. The result is radical flow numbers that help to create big horsepower. As you can imagine, the obvious advantage already went to the LS before we even began building the engines.
The real question becomes, was either engine significantly cheaper or did one walk away as the clear winner? Follow along, and you be the judge. Don't forget to write in to us at chevyhi@ primedia.com and let us know what you think of the results.
Turn Key 402ci
For this build I enlisted the help of Turn Key Engine Supply in Oceanside, California, and engine builder Chris Pollock, whom we have to give major props to. Considering our dyno session was scheduled for the following day, these guys had the entire bullet built from scratch to finish in a matter of hours. Then again, when your business is in the habit of cranking out 40-plus turnkey engines a month, it's just another day in the office.
Now I'm not going to give you a history lesson, but I do want to point out that the LS1 first debuted back in '97, and while it may seem hard to swallow, the newfangled LS variants are already going on their 10th year! Point being, it's not that new, folks. If you aren't familiar with the 6.0L LS2, don't sweat it. It's still in the same platform as the Gen III LS1/LS2 and the 5.3L and LQ9 6.0L truck engines. Matter of fact, all the parts available for this engine family are interchangeable, and it closely resembles the LQ9 truck motor, with the exception of its aluminum construction over the cast iron. Other differences include the relocation of the cam sensor from the rear of the engine to the front and the loss of dual knock sensors in the valley pan, which are now located on the side of the block.
Getting on to the mule, the initial plan was to build on a cast-iron LQ9; however, after pricing out bare blocks, we learned that the aluminum LS2 was only $300 more. Given the similar construction, it only seemed fitting to try something new. Besides, a motor that weighs significantly less only adds to the cool yet functional factor when dropped in between the fenderwells of any street machine. I'll let the following pages reveal the sordid details, including the price breakdown, the components used, and the dyno results.