Step 1
- - Intake pipe
- - Exhaust
- - Catch can
- - Custom tune
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 custom tune is recommended. if you plan on immediately doing more modifications, wait till later for the tuning, but driving modified without tuning for it is not recommended. For intakes, we have found the "Legmaker" brand intakes to be the best flowing on the market for these cars. For thermostat, we recommend 180* for most builds. A catch can is most beneficial to the 6.1L cars as they throw the most oil towards the intake, but 5.7 and 6.4 cars will benefit as well. Sucking oil into the combustion will lowet the octane of the burn and not only rob power but often cause knock/detonation, which is damaging to the motor. Installing a catch can will help cure this. As far as exhaust, you will need to decide what you want to do with the car. A stock exhaust with the cats deleted has been proven to work without power loss up to nearly 500whp, so from the cats back, you're mostly just choosing a sound you like. If you have a 5.7 car, and plan on doing lots of mods, a stock 6.4L exhaust is a great budget upgrade, and will also allow you to use 6.4L based longtubes if you have an eagle motor.
Step 2
- - Ported intake manifold / Throttle body
- - Longtube Headers
- - 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, if you have the old style 5.7. The Eagle 5.7s will accept the 6.1 onto their stock port. If you have a 6.4 car, your manifold can be ported as well. If you have a 5.7 car, a great way to pick up power across the low end as well as the top end is to use a 6.4 ported intake. This will flow much much better vs either 5.7 intake, allowing top end gains while maximizing low end. This would also be the time you'd add longtubes, after everything else has been done. You may want to save the headers though, if you plan to do headwork any time soon, the headers will go on easiest with the heads off. The At this point we've freed up the flow all the way into the head ports and from the headers back.
Step 3
- - Camshaft
- - Head porting
- - Custom Tune
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.