Gen III Hemi upgrade path:
Note: This guide was written in ~2009 or so, and is a bit out-dated, but still useful info. A new guide that is more up to date will be coming soon.
Step 1
  • - Intake
  • - Exhaust
  • - Thermostat
  • - Diablosport handheld tuner

Step 1 is about doing the basic modifications that will get you the most gain out of a stock car, while preparing for future upgrades, and keeping things on the cheap side. Beyond step 1, you're going to be spending some money. Intake upgrade is a good flowing intake, preferrebly cold air style if possible, is a good first modification. It will open up the flow, and when paired with a good, well flowing exhaust, you will pick up more horsepower per dollar than at any other stage of building your car. You may or may not want to eliminate cats depending on your situation with inspections, however removing the cats will yeild more horsepower. The colder thermostat is a very cheap modification that will help reduce heat soak and keep the motor running more consistent. It's been proven over the years these motors just run better with a lower thermostat. At this point, a diablosport handheld tuner is recommended. The modifications are basic, so most cars at this point are safe with a "canned" tune, you can experiment with the 91 vs 93 with hand held tweaks to decide what works best for your car. A full custom CMR flash tune would be ideal, but if you plan on going to stage 2 right away, you might want to save your money for tuning after stage 2.

Step 2
  • - Intake Manifold (6.1L cars)
  • - Camshaft upgrade
  • - Wideband gauge
  • - Custom Tune

Now that you've opened up the flow, and prepared for tuning, it's time to take advantage of that with the next step of modifications. An upgraded intake manifold will be the next mod in the "easy" section to do. We have tested our "Mackbuilt" ported 6.1L intake vs nearly all of the competitors, and it has always come out ahead, even showing huge gains on stock motors on the dyno and at the track. An upgraded throttle body is optional, in some cases we have seen gains from larger throttle bodies, but if you are on a tight budget, that is not where you'd want to spend it just yet. But if you plan to in the future, make sure your manifold is set up for it! For 5.7L cars, the 6.1 manifold is a gain as well, however modifications are necessary to fit this manifold onto a 5.7L head port. At this point we've freed up the flow all the way into the head ports and from the headers back. It's time to take advantage of that intake flow and let the motor do it's thing. A camshaft upgrade will be the next step in bringing in more power, with choices from mild to wild, we have some good cam choices that have gotten us deep deep into the 12s on cam only 6.1s. At this point you've altered the motor enough that you really should have a wideband gauge in the car to monitor the safety of the motor. It's possible the canned tunes may not have things properly covered anymore, and you may wish to correct it via the handheld or go get a custom tune. Especially with the cam upgrade, a full custom tune is HIGHLY recommended at this point.