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Discussion Starter · #1 ·
Hey guys,

I was talking to Keith from BAMufflers a few days ago about headers and he swears that the 4.6 and 5.7 engines are the same dimensions outside so that long tube headers from the 5.7 should fit the 4.6. Surprisingly no one on the forum has confirmed that. Some have said the 5.7 deck height is taller and although headers might bolt up, the clearance might not be there.

I know from the headers back all the exhaust pieces are the same. In fact when I crawled underneath my Tundra, I saw toyota 5.7 stickers on my pieces. So the question is what about the headers? Here is what I discovered by looking at stock photos found on ebay.

5.7 Stock Passenger Header:



5.7 Stock Driver Header:



4.6 Stock Passenger Header:



4.6 Stock Passenger Header:



Without measuring I know its impossible but from the pics it appears that the length and angle looks identical. What's not identical is the type of headers they are. As you can see the 5.7's 4-2-1 design is much better than the 4.6's very restricted log design.

If it is true that the two are interchangeable then it would seem a very inexpensive way for 4.6 guys to gain some power just by picking up used 5.7 headers. Also this would mean that all the 4.6 guys can pick up long tube headers without waiting to hear from manufacture that officially states that its meant for the 4.6.

What do you guys think? Let the debate commence!
 

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I doubt here is much if any power in a set of 5.7 manifolds on a 4.6, Toyota tunes the vvti to work with whatever is on the engine. Meaning, they're expecting the 4.6 logs to flow a certain way and the cams are phased to work with it. With the still tiny runners of the slightly improved 5.7 manifolds I'd say gains would be negligible if any. It'd likely just lose a little bit of bottom torque much like a pair of shorties loses bottom end torque on a 5.7, also, it's about 4hrs per side to change these out, that's a lot of work for such a small gain, if any.

Long tube headers would definitely make power, and I have a sneaky suspicion they would bolt straight up. I've studied, and took measurements, and compared from under a 4.6, it's identical under there. The 4.6 and 5.7 are extremely likely to be exactly the same dimensions. The scavenging provided by the long primaries mimicks the scavenging that the small 2" hidden pipe after the manifolds provides, only the long tubes do it without being restrictive. So what I'm saying is that with long tubes you get to keep your bottom end torque, actually gain some bottom end, and gain mid range, and gain top end. It's a win, win, win!!

If one was to try to bolt on a set of long tubes onto a 4.6 and it didn't work I would offer a full refund. I just wanna confirm that they would indeed bolt on, and I'd bet a dollar they they do.
 

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I wouldn't bother dumping money into a 4.6L. The way to tell it apart dimensionally from a 5.7L is to look for the Briggs & Stratton sticker. :lol:
 

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Don't bother to ask Toyota as the must have a new owner. This guy says he has no boss and his decision is final.

We are sorry for the concerns you are experiencing with the Rock Warrior Wheels on your 2011 Tundra and we regret to hear of your dissatisfaction in this matter.

According to our records, a Toyota Case Manager has thoroughly reviewed your situation and concerns. We note that the Toyota Regional Representative in your area also reviewed all information pertinent to your case, and rendered a decision, declining your request on behalf of Toyota. The decision rendered by this individual represents Toyota’s position.

Our review of the case indicates that all of Toyota’s guidelines have been followed and we concur with the decision. We appreciate this opportunity to further review your request.

If you have any updated information you would like reviewed, please contact your Case Manager, Mr. Jerry Ramos at 1-800-331-4331 x73872
Huh?
 

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Discussion Starter · #6 ·
My take is if BAMufflers can add a few ponies to the engine than so can these 5.7 headers on a 4.6. But as Keith pointed out is it really worth it considering the work that needs to be done to swap it out. I didn't realize the job would take 4 hours! :(

I know log headers are really bad for flow and power and Toyota probably didn't want the 4.6's power level to be too close to the 5.7 which is why it was severely detuned. The log headers seems like a great way to detune. Swapping those log headers for the 5.7's headers would be like swapping it out for a shorty header. Not nearly as good as long tubes but there are some gains to be had.

I messed around with 5.0 mustangs growing up and sorties did provide a decent amount of power for the price as long as you matched it with a good flowing exhaust. Don't see how it wouldn't apply for the 4.6 as long as you have a good mid section like BAMufflers or a catback like the TRD duals.
 

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The 5.7 deck height is 1.1875" (30mm) taller, with the same cylinder heads as the 4.6, it is quite a bit wider. If the down pipes are the same, my call is that the 5.7 stock manifolds will not mate up to the pipes when bolted to the cylinder heads.

For point of reference, we can look at the GS 460 and LS 460. Both use the direct injection 4.6 V8, they are identical except for the tune, air box, and exhaust. The LS has dual air boxes, mediocre tri Y (like the 5.7 Tundra) manifolds, and dual exhaust. The GS has a single small air box, log style (like 4.6 Tundra) manifolds, and a more restrictive exhaust. The LS produces an additional 18 tq and 40 hp.
 

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There is a good chance that the long tubes will work... I'll take some measurements and we can try to determine this....
Haha. Measurements have already been taken;)

They will very likely work. After installing multiple sets of Jba long tubes on 5.7's I can say there is enough room. Like I said, if one wanted to try it and they didn't work I'd gladly refund their money.

Or if someone in SoCal wanted to bring their truck by I would do the $600 install for free!!
 

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send me a free set with a free 8 inch system, and I'll install it myself and record real feedback and pimp your name out for more business all on the right coast
 

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and i'll take plenty of pics of the install and video too
 

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Haha. Measurements have already been taken;)

They will very likely work. After installing multiple sets of Jba long tubes on 5.7's I can say there is enough room. Like I said, if one wanted to try it and they didn't work I'd gladly refund their money.

Or if someone in SoCal wanted to bring their truck by I would do the $600 install for free!!
Wish I lived closer I'd be all over this.
 

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i have my stock headers, i'm not doing any thing with them

there the shortys but should work for bolt up reasons
 

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the shorties would definitely be a good experiment. If one was to dyno before and after stock 5.7 manifolds it'd be interesting to see the difference on a 4.6

I'd also be interested to see a pair of JBA long tubes bolt up to a 4.6, I'd bet $100 the hp difference would be more than 20 with a properly built exhaust system behind em......if they fit:)

I was under a race truck with jba's installed yesterday and measured the clearance all around any possible obstructions, these WILL bolt to a 4.6!! I'd bet shipping to and from anywhere in the lower 48, so in other words, if for some weird reason they don't fit I'll not only issue a refund for the headers, I'd also pay shipping to and from the customer!!
 
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