I have a 2000 F150 4X4 with the 7700 package aka light duty F250. It has the 5.4 engine. An older truck but only has 90K on it so Im going to keep it for a while. I think since it was new I have replaced about 3 exhaust manifolds that keep cracking. I know that was a problem for that engine. My 98 E350 with the same engine has the same problem. I am thinking switching to headers will solve that problem once and for all. I am also bored with the Flowmaster cat back system with the 50 series SI/DO muffler. Louder than stock but not nearly loud enough. Here in NY they are kinda touchy about messing with cats, Y pipes, and O2 sensors. The guy at Midas tells me that moving an O2 sensor just an inch or 2 can throw a code. They are reccommending shorty headers, stock Ypipe and cats and leaving the 2 yr old Flowmaster exhaust. Those 2.5" pipes seem to still be pretty solid and I do like the pipes exiting behind the rear tires. Maybe here in NY keeping the stock cat configuation and just adding headers and a different cat back system makes the most sense. If so, does anyone have a suggestion for a replacement muffler? If I recall correctly, the muffler is not welded. Maybe another option is just to replace the muffler with a Y. If they wont do that, I could handle that myself after they add the headers. Is that going to be TOO loud? I would REALLY appreciate as much input as I can get and ASAP. Currently both manifolds are cracked and she sounds pretty sad. Im ready to spend $1000 or a little more if I need to. Midas has given me a price of $400 to install headers if I buy them. Looks like I can get shorty headers for $400. That leaves me a couple hundred to play with. Id also like some input from anyone that has added headers. What will that do to the sound? Does anyone have a brand suggestion? Last headers I put on a truck was in the 70's so I dont really recall.
Thanks for any suggestions.

 

Shorty headers will be a barely noticeable sound change. Your best off getting them if you OEM manifolds are leaking, stock 4 cats for emissions reasons, Magnaflow free flowing Y pipe, and a Flowmaster Super 10 SI/DO muffler .

 

Im curious why you are suggesting that setup. Not arguing but curious. Why do you suggest the flowmaster instead of something like the Magna bullet. Since I am "new" to aftermarket exhaust (its been 30 years since I put headers and glasspacks on my old truck) I want to find out as much as I can before jumping in. I think the headers need to be done pretty quickly. The manifolds are getting worse daily. Is there a brand of shorty headers that seem to be more popular? If I run them in to my shock Y pipe is there any advantage to then Y-ing into 2 bullets as opposed to some SI/DO? Please excuse me if I am asking obvious questions. I realize there are many options but I am open to almost any suggestions.
Thanks all

 

Ya Darren...why are you suggesting a sido flowmaster 10? I thought you were better than that haha. JBA, BBK, Edelbrock, and Pacesetter SS shorties are all popular brands. You can run 2 magnapacks (which is what you described as magna bullet), which then in turn eliminates the Y pipe, and either an X or H pipe as a crossover. You will get the best gains and most free flowing exhaust by eliminating your Y pipe and running dual mufflers, vs SIDO with a Y pipe.

 

Im just thinking out loud here. I apologize if it sounds like a copout but how does this sound? Going with the shorties is a given. Staying with the factory crossover and 4 cats (possibly switching out the rears for high flow?) I assume that is 2 1/4" tubing. From the crossover, running 2.5 into a Y (2.5 in/2.5 x 2 out, in to 2 of the dynomax bullets then out at 45's. Is there anything good or bad (other than double the cost for mufflers) with running 2 bullets as opposed to the SI/DO? I realize its not a true duel setup but seems like it would have to be better than the 50 series SI/DO flowmaster thats on there now.

 

A true dual setup completely eliminates the Y pipe. You can run either 2.25" or 2.5" pipe from the headers all the way through the mufflers. 2.25" having low end tq gains vs 2.5" gaining in the higher rpm range. If you tow then 2.5" would be ideal. I would recommend true dual (dual mufflers, no Y pipe, and either an X or H pipe crossover) vs 1 bullet and dual outlets. If you do the true dual setup, then youll be the first one on here to do it with a 97-03, so i recommend that!

 

I talked to a shop this afternoon. Not a muffler shop but a guy that does a lot of custom work on performance vehicles. he said he was familiar with the 4 cat system and sounded excited to work on it. He is proposing deleting the 4 cats and going with 2 performance cats and true duals and said he would be able to keep all the O2 sensors performing properly. He is familiar with the 7700 F150 and said he has done duals on several 5.4s and can make it sound real pretty... Loud but pretty. He agreed that either an X or H would help make it sound even better. Sounds like he really knows what he is talking about. Now I just need to get a chance to visit his shop so he can take a look at it.

 

Good. Sounds like he knows what hes doing. Any idea what mufflers your going with?

 

I see a lot of guys on here talking about the Dynomax bullets. I think its hard to tell what they really sound like on line but if that many people like them, I guess Ill see if I can go with them. I suppose its possible that if he knows his stuff he may have something in mind and Im open to that too. Anything has to be better than the flowmast 50 and 2 cracked manifolds

 

I would go with those or magnaflow magnapacks (14" round).

 

Ive also been paying attention to the discussions on high flow cats. Its all a little confusing. I understand the correct part is based on weight. Since this is the 7700 model, the gvw is a bunch higher than any of the normal F150s. Should I be looking at different cats than you use? Is Magnaflow the cat of choice? On their website I dont see a direct application guide for this model truck. Is there a better choice if I am going to be deleting rear cats? I just want to consider all my options. If I am going to build this system from headers to X to tips, Id like to do it just once and build it as efficient as possible. I wont say money is no object but In the grand scheme of the whole system and labor, whats a few more dollars? Thanks again. I reall feel like I am learning something the further I dig.

 

Darren is the cat guy to talk to.

 

The cats just need to meet the engine GVWR ratings. Not about trailer pulling and such.

The only direct application Magnaflow cat system for your truck is also a 4 cat system. Goal is to only get two.

 

WTF

 

yeah ummm Im speechless. Ill just pretend I didnt see that