How much horsepower should i expect from headers?
 

I have a 2002 mustang gt with a stock engine. About how much difference would i see in horsepower if i added headers? And also would it make the engine louder?

longtubes will get you the best gains, and yes it will make your car louder..i know because I have them on my 2002gt...my 3rd gear pulls so much harder with them...

10-15 with longtubes and a full catback. 2-3 wtih shorties. 8-16 with midlength's by all reports. it's not worth the 500 bucks for the headers and the 800 for the install.

yeah i would want to get the longtubes but i guess there too expensive for me rite now.

Expect even more impressive gains w/ a set of cams. However, if you want them, do it yourself, this way you don't need to go on welfare afterwards.

wtf i hate wen ppl say parts arent worth it

horsepower is horsepower

You may gain hp but you loose torque. That's why it should be one of your last mods before you add a power adder or cams.

i did LT's as one of my first mods and yes their was a little low end loss but it does pull harder through the upper rpm's, no regrets here for $300 install...

Yeah, but a normal install for labor is $400 to 700 installed plus $500 for a good set of headers. I would save up for a power adder before I did that.

I don't know how you guys noticed a loss down low but I'm getting better mileage both city and highway running below 2500 rpm which means there can't be that much that is lost. Maybe the addition of cats helps out?