This is a story that many traditional small-block Chevy guys don't want to hear. They think the new Gen III and Gen IV small-block engines from GM are too expensive to build and don't make that much more power than the old engines. The truth is that while these new-generation engines are different and the parts are sometimes more expensive, there are ways to make affordable power-big power. The more progressive car crafters have already embraced this new technology and are enjoying the powerful fruits of their willingness to try new things. While there's always room for both small-blocks, if you are serious about the horsepower game, it's no longer prudent to ignore these late-model engines. They thump.
We've been watching the used Gen III engine market for the last couple of years, waiting for the right time to jump into the new-Gen world. While these engines are metric and look a little funny compared with the tried-and-true small-block Chevys, the reality is they are still just four-stroke, two-valve motors. And in many ways, they are far superior to the engines we grew up with.
Most of the media attention has been focused on the aluminum 5.7L LS1 or the latest 6.0L LS2 engine. The LS1 is becoming more affordable every day, while the LS2s are still too new to be considered budget material. While all-aluminum means less weight, we wanted more displacement. This led us to the iron 6.0L truck engines. These 364ci motors are really just 4.00-inch-bore versions of the LS1 with iron blocks. As you can see in the displacement chart, the entire Gen III family is similar to the old-school 283-327-350-400 small-block family tree.
The 6.0L's larger 4.00-inch bore is important because we wanted to test the horsepower potential of the latest L92 heads that just came on the market from GM and are being used on the new '07 L92 truck engines. Because of their larger valves, these heads cannot be used on a bore smaller than 4.00 inches. But you'll have to wait until next month for that part of the story.
Even with stock iron truck heads, we were able to crank out over 480 hp with a mild cam from the carbureted 6.0L engine for less than four grand. We were impressed knowing that with more cam and some speed stuff, 500 hp was well within reach
The Used Motor Game
Our search for an affordable, used 6.0L engine led us to LKQ, a nationwide chain of recycling yards that offers take-out engines from late-model vehicles. In an online search, we found a 6.0L engine out of a truck for $1,100 at the LKQ in Santa Fe Springs, California. We were able to obtain the engine without the A/C compressor, starter, power-steering pump, and alternator but still with all the brackets and pulleys.
Since this is a nationwide chain, often the engines will be located in different states, which will require shipping. Shipping costs vary depending on how far the engine has to travel, but according to Brian Sebring of LKQ, they average between $225 and $275.
Among the engines we searched, we saw several 5.7L and 5.3L engines that would also make great starting points (for a little less money) if a 6.0L isn't to your liking. According to Sebring, the 5.3L engines can be had for less than $1,000 depending upon their condition. LKQ pulls the engines, tests them on a stand, and then sets them up on a pallet for shipping. It doesn't get much easier than that.
Of course, LKQ is just one source for used engines, but the company has 65 yards throughout the country, so it makes it easier to find the engine you want.
 We uncovered a ton of power...  We uncovered a ton of power in this iron 6.0L Gen III small-block with just a cam change and headers. |
 Used engines are becoming...  Used engines are becoming much easier to find at decent prices. The LQ4 engines began appearing in 1999 in trucks, SUVs, and Cadillac Escalades. Early engines had iron heads; later-model, 6.0L versions used aluminum heads. |
 Everyone knows heads are the...  Everyone knows heads are the horsepower source. These stock, iron 6.0L heads feature 2.00/1.55-inch valves but can deliver almost 500 hp with a mild cam. We didn't touch these castings. If we had, we could have easily made over 500. |
 The first thing we did was...  The first thing we did was simply plug the MSD timing and rev control box into the factory ignition harness. Then we plugged the serial-port connection into our laptop computer. |
 The MSD 6LS ignition controller...  The MSD 6LS ignition controller is a plug-tune-and-play deal and includes an ignition-curve software program that uses one easy-to-understand timing-curve screen. To change the amount of timing or the shape of the curve, merely click on any of five data points and move the timing point where you want it. Then just save the change to the program and you're done. |