manifolds or headers?
Thread Starter
|
Freshman User
Joined: Mar 2003
Posts: 30
Likes: 0
manifolds or headers?
I am new to this site and a converted chevy guy so I am sure I will have a lot of questions in the future. Right now what I am wondering is about stock exhaust manifolds on my 93 F-150 with the 300 I-6. I am reading that a good upgrade for the carbed versions are the manifolds off from the EFI versions, but what about upgrades for the EFI versions, are headers worth the money?
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
manifolds or headers?
Strictly for power production I say go with headers. Be warned in advance that they are not a true bolt on. You must make modifications to the alternator bracket for the #1 tube to clear, and then the tube is less than 1/4" from the alternator, so you need some heat shielding. The good thing is that you won't be able to fit the stock heat shield between the intake and headers, so you can cut a piece of it off and use it for the alternator. Of course that makes the intake heat up. You will also have to run completely new exhaust (duh), extend the O2 sensor harness roughly 6", replumb the EGR system, and deal with a lean condition above around 3200 rpm. The lean condition can be somewhat fixed using larger injectors and an adjustable fuel pressure regulator (from a 5.0 Mustang, custom bracket required), but then it is way fat on the low end and the PCM doesn't know exactly what to do with it. The O2 sensor also tends to cool off in the winter and cause an SES light. Even through all this I got a huge gain (7mph in 1/4 mile) from the headers alone.
Senior User
Joined: Feb 2003
Posts: 215
Likes: 0
From: The best is the U.S.
manifolds or headers?
Stick with the EFI manifolds. Cut them right behind the O2 sensor and put in a High flow dual exhaust setup. The O2 sensor is a 4-wire, self-heating (at least on a '93) so you should have no problem with it. I would like to line up with a 300 sporting headers and put this extra power theory to the test! My truck is flowing all the exhaust it can produce and then some. Best of all this setup doesn't require anything other than new pipe. 
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
manifolds or headers?
Originally posted by HardworkinFORD
The O2 sensor is a 4-wire, self-heating (at least on a '93) so you should have no problem with it
The O2 sensor is a 4-wire, self-heating (at least on a '93) so you should have no problem with it
I lined up with a F150 XL at the track a month or two ago. Both trucks with a 300, but mines a Lariat, both 5 speed. Not even a race. Once we were in second gear the other truck just got smaller in the mirror until he was about 100 yards behind at the finish line. Headers are for more than flow.
Like I said, unless you just want all out power they aren't worth the investment to get them on the truck. They are much better than the EFI manifolds even with the lean condition at high revs. There's and old racers's saying: The worst header is better than the best manifold. I havn't found a case yet where it wasn't true.
Senior User
Joined: Jul 2001
Posts: 470
Likes: 0
manifolds or headers?
Does anyone have a pic of the EFI manifolds entrance and exit or have them handy to measure? I've been seeing people say for months that the EFI manifolds 'flow as good as a header' (obviously others are speaking up in this thread) but i'm having a real hard time seeing how those manifolds can flow better than the 1-5/8" primaries into 2.5" collectors on my hooker. Oh, and what, $120 for the pacesetter header and a quart of that 1800 degree paint for $10. I don't consider that too cost prohibitive.
-=Whittey=-
-=Whittey=-
Trending Topics
Senior User
Joined: Feb 2003
Posts: 215
Likes: 0
From: The best is the U.S.
manifolds or headers?
Silver Streak is quite right about the function of the O2 sensor, however we have been seeing some very cool weather and I haven't had any adverse effect (i do live in the south however and temperatures below single digits are the lowest without factoring in wind chill). As far as the headers go your conviction sways my opinion. My post was not meant to slight your professional opinion, but only to convey my experiences with this arrangement. I am the first to admit that my primary trade is as an electrician. Wisdom says to stick with the manifolds and see what you think, if you don't like them you can always make room for headers later. If you like I can explain to you how to test the O2 sensor for proper output if this is a concern.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
3 Best / 3 Worst Parts of Modern Ford Ownership
Brett Foote
10 Amazing Upgrades That Solve Common Ford Truck Owner Headaches
Pouria Savadkouei
Every 2026 Ford Engine Explained
Brett Foote
10 Ugly Ford Trucks That We Still Kinda Love
Joe Kucinski
10 Things Every Truck Owner NEEDS (2026 Edition)
Michael S. Palmer
Rezvani's Latest Post-Apocalyptic Monster Is a Ford F-150 Raptor Underneath
Verdad Gallardo
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
Posting Guru
Joined: Dec 1999
Posts: 1,903
Likes: 2
From: Copley, OH
manifolds or headers?
I think "as good as" is a bit of a misstatement. The EFI exhaust manifolds clearly represent a quantum leap over the older single piece manifold and add performance throughout the entire RPM range of the engine. Headers are also an improvement over the EFI manifolds but they probably offer very little additional gain on a near-stock engine operated in the stock RPM range. Open up the intake, put in bigger valves and a stronger cam, run the engine to 5500 and headers become a necessity. Throw in the issues of noise (not everyone thinks more is better) corrosion and hassles from the smog-***** and the stock manifolds look even better. On a stock engine, there's better places than headers to spend money.
Postmaster
Joined: May 2002
Posts: 3,241
Likes: 3
From: Broken Arrow, OK
manifolds or headers?
Originally posted by StrangeRanger
On a stock engine, there's better places than headers to spend money.
On a stock engine, there's better places than headers to spend money.
Senior User
Joined: Apr 2000
Posts: 188
Likes: 0
From: Latrobe USA
manifolds or headers?
Hey Whittey,
What's your e-mail, I have a EFI 300 sitting in my driveway out of the truck I can send you pictures and measurements tonight if you want. I also have the front exhaust pipe for that also.
Let me know,
Aaron
What's your e-mail, I have a EFI 300 sitting in my driveway out of the truck I can send you pictures and measurements tonight if you want. I also have the front exhaust pipe for that also.
Let me know,
Aaron
Thread
Thread Starter
Forum
Replies
Last Post
Monte1go
Ford Inline Six, 200, 250, 4.9L / 300
15
Aug 29, 2016 02:46 PM
lorenzo_mest
Ford Inline Six, 200, 250, 4.9L / 300
8
Aug 20, 2010 12:14 PM
b.bixel
Ford Inline Six, 200, 250, 4.9L / 300
11
Jan 28, 2010 09:27 AM