Hello everyone, my name is Eric, and I am new to this section of FTE. I just bought a '94 F150 XL 4x4 5 speed manual with the 4.9L 300Ci I6. I am looking to really wake her up, but am having no luck with my research on google, summit, jegs, or with the search tool on here. So I am looking for experiences from people who have this motor, and have modded their exhausts.
What I am looking to do is build a custom exhaust, starting with the header back.

• I would like any feed back from people who have installed performance headers on their I6. Which should I buy? Important factors for me are; low price (but not absolute), single outlet (so that i dont have to buy 2 CATs and 2 mufflers), and it has to be able to bolt up without any alterations to the truck itself. I have a welder and tools, and such, but i just dont want that headache.
• Also any suggestions on High Flow CATs and Mufflers would be great. I am looking for as dee a rumble as I can get with this inline 6.

Again, low price is important to me, but it isnt my top priority. So anyone with this motor, that has any suggestions, or experiences to share, it would be greatly appreciated.

Thanks for all your help in advance,
Eric

 

On an I-6 first thing is to get a hi-flow cat and muffler, hope this helps

 

So you think that I could just go ahead and skip the headers all together?

 

is it 2.25" piping that our trucks are running?

 

I would skip the headers, and add a k&n air filter. 2.25 sounds right on the pipe size. remember this cat and muffler was IMHO overkill on these trucks.

 

Thats a relief, because thats more money I can spend on the CAT and muffler. Im good with choosing the muffler, but do you have any suggestions on which CAT I should go with? ...It may sound stupid, but which air filter are you talking about? Where is it located? Ive done a couple of exhausts on my previous vehicles, but never messed with any air filters related to them...???

 

K&N air filter (think intake side). Magna flow or comparable for the cat, the exaust wont help much unless the engine can take in the air it needs.

 

Ok, I see where your coming from. So just a dual-in single-out cat should work pretty well? or am I going to need to buy 2 separate ones? (The stock headers have dual outlets correct?)

 

Dual in single out should work fine, i dont feel, u need more than one cat on the truck. it should be dual outlet header pipe

 

Your 94 already has a split manifold. I would not bother with headers on it. It doesn't move that much air and is a lower reving motor anyway. I would get a high flow cat and run a good straight through muffler like Magnaflow or Dynomax SuperTurbo with 2.5 inch single exhaust.

Keep your stock air box and intake tube its a great setup and already pulls in cool air. Stick with a good OE type air filter like Motorcraft, Wix, Purolator etc.

By the way stay away from KN CAI, TB spacer, snake oil spark plugs etc.

 

Yeah, the carbed guys feel like the struck GOLD when they find a FI 300 and ****** the manifolds. Keep em, run a good Y pipe to a single high flow cat and high flow muffler of your choice. I ran a gutted cat and a Flowmaster 40 out the side before the rear tire and it sounded AWESOME and the truck ran great!!! Good luck!
Matt

 

ok well... where do you live??? If you live in a state that does the emissions testing then go with a high flow magnaflow cat... if you don't (i know someone will raz me for saying it but...) delete your cat! I have a I6 in my 88 f250 and have deleted the cat and ran 2 20in "glasspacks" off the headers into a single 2.5in exhaust. it breaths really well and the i6's aren't that loud without the cat (depending on muffler of corse). I agree the headers aren't worth buying and stock was done just fine. Get a cold air intake from K&N for a couple hundred bucks and the i6 will be able to draw much more air. google "K&N 57-2503" this is the non mass air setup so if you have MAF you'll need a different one...

 

63-1014 is the K&N part number for newer 4.9L motors... evidently both are with out MAF sensors so you just have to keep your MAF metter plumed in if you have one...

 

Check out the straight six forum on here. On the top, there is a sound click thread that let you listen to what people have done with there I-6's!

 

My set up too! Sounds great. Don't look for V8 performance out of your 4.9 and you will learn to love what it is....a little torqster I think the right gears and a good clutch are the real deal with this combo. The 4.9 is excellent on gas and will out last all the others.