At least he didn't include "cheap"; I shake my head at that trifecta.

 

Imo it's really not worth regearing just to go to 3:73s though. I know you would loose some gas mileage, but 4:10s would give it some nice "pep" when you push the gas peddle.

 

I have 4.10's. It will tank your mileage on the interstate. I have to stay below 70 to get half way decent on the interstate.

 

Yes that is what I would expect 4.10's to do. I think I'll just keep the 3.55's as even if I do these mods I won't keep the truck more than 2-3 yrs. Currently my truck has only one small scratch and 2 small chips in the hood. Then there is a little surface rust in the bottom of the tailgate that I've been watching closely and trying to keep cleaned off. Other than that it's still very nice and in almost new condition.
If I can get 8-10% bump in power and keep current MPG's then the aforementioned mods -gears would be worth doing. I'd also mount a set of really nice wheels on the truck to give it a fresh look.
If I'm really not going to get a performance bump from doing all that (CAI, Cat Back Exh, SCT MPT Programmer) then I'll just go buy a new truck!

So I just read up on something called a GOTTS Mod to the factory airbox, seems that's the better way to go over the $260 CAI.

 

The biggest problem is fuel. The facore injectors are running any where from 80-85% duty cycle in complete stock form. A set of longtube headers and correlating exhaust with a good filter and tune will net around 10-12% rwhp. But you will have anywhere from 5-10% decrease in mileage. These older modular aren't very high tech or efficient.

 

Well I just got a Flowmaster Catback exhaust installed and while it does sound a lot nicer I can't say it feels a whole lot different. I was not expecting to feel it though until after the tuner is installed.
I'm guessing that results are going to vary a lot from person to person based on many factors, for one thing I'm here in Utah and at 4,500 ft elevation so I have lost a lot more than someone at sea level. That said I think I should have a lot more to regain from these mods, but maybe I'm just kiding myself.

 

Flowmaster won't help at all. It's not a free flowing muffler. Air density is key. Being about a mile up your SOL. N/a you won't see anything really. Slap a small supercharger on it and it may be a different story.

 

Think I'm going to try the SCT / MPT and see if that helps. From what I've read I should see some gains. Carcrazygts, you seem to be the only person saying that this is all a waste. Do you have any data to back that up, if so I'd live to see it before I spend more money on this.

 

I just installed a stock tune w/SCT on my 2005 4.6....there is a difference
I've had the truck since new, so I know what it drives like
More power, better shifting w/just the stock SCT 87 octane tune
I have 5 custom tunes being sent to me
I filled up w/93 octane ...2.75 per gallon w/discount...still 1/2 tank 87 in there
I drive less then 4k miles a year, so switching to 93 octane will cost less then $100 per year
Hoping to put some Funability back in the truck...larger tires in the Spring will decrease my gas mileage

 

I've spent the money and bebeen down the same road your traveling. I live at sea level and saw huge gains. But your close to a mile up. I've had my truck in Denver and it was a dog.

I'm not saying there won't be any improvements. The gains won't be nearly as noticeable due to the elevation difference. What I outlined earlier will make you some more power but you will sacrifice mileage. They go hand in hand with these trucks.

With longtube headers, high flow cats, full 2.5 exhaust, free flowing muffler, gotts mod, and tunes you should see about 30rwhp/45-50tq. This calculations at sea level.

I have high compression cammed 5.4 with great tuning. My truck has been flex fueled. It primarily runs on E85. But even on pump fuel its not as fuel efficient as it was when it was stock. Even with all my engin work it only make 320/360 to the wheels on E85. On pump fuel (93) it's 305/350. Which is around 80hp increase to the wheels. Mind you I have a 4wd with 4.10's and slightly bigger tires. If ithe was 2wd or even stoc gears and tires it would make more on the rollers.

I had MPT tunes at one point in time on my 97. My 03 is currently using them. On a dyno my 03 only saw 16hp/30tq. It's a bone stock 5.4 with a AFe filter and gotts mod.

To the guy posting about owning a 05. Your 4.6 truck has quite a lot different than the 10th generation trucks. Of course you will notice a difference. Most of which is driving manners and throttle response due to the electronic throttle body.