mself52

you arent going to lose 3mpg if you drive the same way you always did.... ppl lose that when they are constantly flooring it b/c of the crazy acceleration that 4.10 gives you that the 3.27 didnt .... but only thing i regret bout my 4.10's is that they arent 4.30's....drove to houston last week cruised 80mph the whole way and got 23-24mpg the whole trip

luckymckay21

Ok guys. Looks like the intake with the throttle body and plenum for now. Then it's time for some gears. Thanks for all the help

stangc83

ok well it looks like you didn't read your mustang magazines. well mm&ff did an article on putting headers on a n/a 4.6 well they came out with negative hp until about 4000. once you hit above that you get about 10 hp. below 4000 you are at 9 gain and below about 3000 you are negative 5. so what you need now is a bigger maf, bigger injectors and a full bold on assy. like pullies, tb and plenum. then they recommended a cam since you have soo little hp gain in the mid range. so to all f you, unless you are planning on getting the s/c or t/c do not get the headers. you will not get as much backpressure as a 5.0 will, and your car will sound really really hollow.

HIGHLANDER

[sm=WTFsgign.gif]

No offense but...
Are you trying to tell us that you don't gain HP by installing headers?
Have you ever had a car with headers installed on it?
With the right headers, exhaust setup, and proper tune you will notice a big difference in HP. (yes even in non-supercharged / non-turbocharged vehicles)
Trust me I have had several including a '79 Vette (heavily modified, naturally aspirated 500 + RWHP) with full length Hooker Headers with Sidepipes. To tell me that there is no benefit to installing headers on a naturally aspirated car is absolutely insane!

A hollow sound? Give me a break man.

stangc83

that was on a vette with a y pipe right. mustangs have x or h pipes. and down in the low rpms you are going to lose some torqye and hp. up at the higher rpms you are going to gain, you just have to wait till you start getting more flow. but i just looked at his setup and was going to say that if you dont have a cai then you would also restrict the flow. and you may just be having too much flow and not enough fuel with that flow. you can get all the flow you want but you just need to give the car the fuel to ignite.

XxphantomsnypzxX

so wait exhaust is bad unless you actually have more intake mods?

stangc83

yeah you need air to blow out air

Theorem1

Same thing happen to me. The full exuast system was the the first mod I put on(Mid headers, X pipe). Once I put on the CAI and the 3:73's with a tune the beast was awaken. I did it backwards with the exuast. Didnt know it then butt it makes sense.

HIGHLANDER

No the 'Vette did not have an H-Pipe, Y-Pipe, or X-Pipe. Sidepipes on Corvettes are TRUE sidepipes (not the fake sidepipes you see on Mustangs). They consist of headers which actually run along the side of the car. The headers connect directly to the mufflers which also run alongside of the doors. Let's put it in simpler terms: If I opened my driver side door I could put my hand down and touch both the header and the muffler (would not attempt to do that after it was running! [sm=badbadbad.gif]). The headers and mufflers where both chrome plated and gave off a tremendous amount of heat. When you get out of 'Vettes which have sidepipes on them you have to make sure not to touch the pipes unless you want to have a serious burn!

The 'Vette was louder than any Mustang I have ever heard - bar none! I would set off car alarms when driving by parked cars. You could hear that car coming a mile away! Man I wish I never sold that thing!

'79 Vette mods:
* 350 4-bolt main block
* 202 fuelie heads
* High performance cam
* High performance lifters, rockers
* Edelbrock high-rise single plane intake manifold
* Holley 650 double-pumper carb
* 3.70 Gears
* 3 speed Auto with Shift Kit
* Rebuilt high performance independent rear suspension with fiberglass leaf springs
* Full-length Hooker SuperComp chrome race headers with 1 7/8 inch primaries
* 4 inch chrome sidepipe exhaust

* Too many other mods to list... besides this is a Mustang Forum!

I do agree with you that the Mustangs do have to breathe in order to make more power. It is definately a good idea to do the other mods to help the car perform better. However, headers do work extremely well on naturally aspirated Mustang GT's (especially long-tubes with 1 5/8 inch primaries).

GodAmGT00

A Vette is a much different beast than a 4.6 Modular Mustang, if you haven't checked recently.. The tests have been done NUMEROUS times, and this topic has come up a bunch before, or have you missed the other 100 header posts a week?? C'mon guys.. It's on paper, that w/ the shorties, the car WILL lose some NOMINAL power/torque under 4000RPM's.. That's where the argument needs to end..

Now, after 4000RPM's, you start to gain power, not quite as much as L/T's (better scavenging, more effective velocity, etc) but it's there..


JT