Bob99GTConv

My mechanic and fellow Ford Mustang owner said I would get much more power with shortie headers/pro chamber high flow cats than a 70mm throttle body/plenum upgrade. He said they dynoed a Mustang GT after a throttle body upgrade and didnt see even a 1hp difference but they didnt do the plenum. He also said long tubes were not worth the hassle and to go with shorties as I am only looking at a 5-6hp difference between shorties and long tubes. If you have done both to your car and had it dynoes after each let me know. If you are guessing, well please dont , haha. Just trying to see where to head next. Im not really a neewbie, Im just use to running 67-69 Camaros so I didnt have to worry about all this, BUT IM A CONVERTED MAN, lovin the stang baby!

devinsteen

Go with the headers and the x-pipe man. Most people here will say to go with long tubes....they produce much more power than shorties. I had a 75mm TB on my GT an didn't really notice a difference. I took it off and bought a H-pipe instead. I could feel the hp gains right away. The TB/plenum is going to give you 10rwhp maybe (although it is a good mod). But the headers and mid-pipe will give you around 15-20hp. Exhaust mods first[sm=goodidea.gif]

mdvaldosta

tb/plenum is only worth 6-7 rwhp, you'll get nearly twice that with just an x-pipe

roundman

listen to your mechanic and Mustang owner, he knows what he's talking about. do the exhaust work first and you will get the biggest bang for the buck right away. the larger TB won't do much unless you change the cam and heads to use the extra air.

jdaniel

Shorties are worthless... there are guys all the time coming into my raceshop complaining about getting them instead of the long tubes.

roundman

I respectfully disagree! (unless you're talking about the mod motor 4.6L cars)
My MAC equal length shorties on my '88 5.0 have been good power makers since the day I installed them along with a 2-1/" cat back exhaust system. and they were even better after I installed the off road H-pipe too. and they were lot easier to install than long tubes too!

Redline03GT

Your mechanic is right.

Dan04COBRA

Shorties are fine. Do it...

yellowstang98

if i am not mistaken... ya there might only be a 5-6 hp difference from the ltbs and the shorties but arent those numbers relative to stock mustangs. i mean i look at it this way, wouldnt you want to do mods that allow for the optimum power making not only now but as you further mod your car. i mean i know that this is an extreme example but say that you have aspirations to one day throw a blower on that GT... why dont you try and find the hp difference for a blown GT with shortie headers and then with ltbs. ltbs are more expensive and the install is quite a bit harder but would be well worth the price, especially if you had bought shorties paid to get them installed then when you started to put down bigger numbers realize that you should go with ltbs, and then have to buy the ltbs and pay to get them installed after already buying shorties. ltbs all the way baby!!!!

jdaniel

And not to mention that if you ever wanna force induct the engine then the LTs are the way to go or you will be changing them out on the FI install.