Never before have so many enjoyed so much for so little.
Take a look around. We are smack dab in the middle of the second major Muscle Car era, and this one has taken the power levels to new heights.
I love a DZ302, Boss 429, or Hemi Cuda as much as the next guy, but line one of these muscle motors up against its modern counterpart and you quickly realize how fast things are today.
This modern muscle has plenty of carryover for average enthusiasts, as the LS, Hemis, and Coyotes of the world eventually find their way into wrecking yards.
It’s amazing that you can grab a used LS (as well as a Gen. III Hemi or Coyote), high mileage at that, add a cam, springs and boost, and make four-digit power.
The icing on the cake is that this four-digit power level can also be driven on the street, and get good fuel mileage to boot. Much of the credit goes to the advent of modern fuel injection, but the influx of affordable boost is responsible as well.
Though our test mule was already fortified with a few mods, this can easily be duplicated with a junkyard version with equal success. That we already had a suitable 4.8L ready to rock, made things that much easier for us.
The 4.8L we’re testing started out as a high-mileage wrecking rat, but some poor choices on our part meant it had to get a fresh set of pistons a few years back. A quick bore (.010) and a new set of forged slugs took care of the damage.
We installed a set of JE forged pistons that featured 7-cc domes to help with our static compression when running naturally aspirated applications.
It also worked under boost, albeit with proper timing, intercooling, and fuel. The forged slugs were swung on a set of well-used, Gen 4 rods, because why not step up from those weak Gen 3 rods?
Never mind that we have made hundreds of pulls on them over 1,000 horsepower, but off they came! The rest of the bottom end included a stock block and crank, along with Fel Pro MLS head gaskets and ARP head studs.
To help this test motor make some power, we upgraded two things — the cam and valve springs.
The stock LR4 cam had long since been swapped out in favor of a Stage 2 turbo cam from Brian Tooley Racing. The cam was combined with a set of 26918 valve springs from COMP Cams. This allowed the 4.8L to not only rev, but actually make decent power.
Remember, the gains offered NA can be multiplied under boost, so a little bump in power becomes much bigger under boost. That’s why we go to the trouble of camming the LS in the first place. The cam and springs were combined with more stock stuff, including the factory 706 heads and truck intake. Sure, there are sexier components to install on the 4.8L (like TFS 205 heads and a Fast LSXR intake), but the stock stuff worked just fine, and it came with the motor when we plucked it from the yard!
Run in this trim on the dyno, the little 4.8L produced peak numbers of 409 hp at 6,600 rpm and 367 ft.-lbs. of torque. Now it was time for boost!
Boost was supplied by the S475 turbo from Summit Racing.
The twin-scroll, T6 turbo featured a 75-mm compressor (inducer) and an 88-mm turbine (exducer). The turbo also featured a 1.32-A/R ratio turbine housing and the ability to support near 1,000 hp on the right application.
We were not looking to push our test motor there, but it is always nice to know there was a little extra after you get tired of running just 10, 12 or 14 psi (pick your number — you will crank up the boost-they all do!). The turbo was installed with a custom turbo kit which featured a truck manifold, a custom Y-pipe, and a pair of Turbo Smart Gen 5 waste gates.
Turbo Smart also supplied the Race-Port BOV, though they constantly yell at me to upgrade to the latest version. What can I say — I’m OG BOV! Boost from the Summit turbo was supplied through an air-to-water intercooler from ProCharger.
Run first at 7 psi and a soft tune on pump E85 (our low-buck race fuel of choice), the turbo 4.8L produced 576 hp and 525 ft.-lbs. of torque.
After stepping up to a solid 16 psi, the power needle showed 829 hp and 761 ft.-lbs. of torque. Take a look at the power curves in the supplied graphs and you can see the power outputs at different boost levels. You can also see that the turbo was ready to support even more power, but how can you complain about an 800-hp 4.8L?
Especially when it was so easy.