ORIGINAL: Martin123

OK, I've decided to purchase the JBA Shorty Headers. I already have a CAI with X-Cal tune and Borla Cat-back. Now, do I "HAVE" to dyno tune or download another tune from SCT "OR" can I just bolt on the headers and be happy!?

ORIGINAL: bahbahblacksheep


2005 Mustang GT already comes with its version of shorty headers stock...that's why they don't recommend these for the '05. You should get the long-tubes for a ~20hp gain.

Now with headers, you should get a tune because you are affecting air flow in a big way.

ORIGINAL: F1Fan


Hi Guys,

The difference in power between JBA shortys and JBA long tubes is not as great as you may think. Much of what you will see at the wheels with the '05 GT's is very dependent on what you have done with the rest of the exhaust and intake not to mention the custom ECU program or tune. Long tubes are a pain to install and you will lose ground clearance if you keep cats in the system.

The there are a couple of advantages with JBA shortys over the other shorty designs, first is that they use a near equal length design using longer tubes than most other shortys for the '05 V8's. JBA shortys are also very made from very heavy gauge SS tubes with extremely heavy mounting plates on the head side for a no leak fit and the primary tubes are the RIGHT SIZE for a Hi-Po street engine, they are NOT over sized like some of the other headers bing sold for the '05 GT's. This is why JBA's shortys have the potential to make the best torque and horse power. The down side to JBAs headers is that the '05 engine is mounted with very soft mounts and because JBA used as much space as they could to get the length the needed you really need to install firmer motor mounts when yoiu install the headers. They will be out anyway so you may as well replace them at the time you install the new headers.

There is probably no more than a 5-8 HP difference between the JBA long tubes and the JBA shortys for an all motor 4.6l engine with bolt-ons. For an exhaust system that is very free flowing (from the headers back), JBA long tubes may be at a disadvantage making the difference even less. For example, if you have the JBA shortys installed with 2.5" high flow cats with a 2.5" X-pipe with the stock mid-pipes and rear Ford mufflers you'll get better torque with comperable HP. If you install JBA long tubes and a no-cat X pipe with a straight through rear muffler design like the Loudmouths you will kill your torque and still only have the same HP if you are lucky. The GT's 3 valve engine is sensitive to back pressure and you need to keep some or you will lose torque and power, more here is not really better for an all motor combination. With a blower or motor on squeeze the larger flow will help but on an all motor combo it will hurt your area under the curve.

Consider the whole combination before you jump on the long tubes no matter who makes them.


Hope this helps