Hey everyone,

Since I didn't have luck finding a thread that answered the question I figured I would start my own. I'm deciding wether or not it is a good idea to install headers when I do an engine swap. I have a 95 4runner, and will be pulling out the 3.0 for the 3.4. I figured at some point, someone on these boards has done it.


1) The obvious question. It is worth it? I'm not looking for a rocketship here, but a modest improvement in performance would be nice.

2) Are they a PITA to install? As I said, I would be installing these when I do the swap. If there are a bunch of work arounds involved because they don't fit very well I don't think I'll bother.

3) Are there any brands that anyone could recommend? I heard that Thorleys are good, but I know they are not the only option.

Any additional two cents are more than welcomed.

Thanks guys.

 

I think I've read in one of the builds that Downey headers are a good choice. To be honest I'm not 100% certain on the extra performance from them. Also ORS has a write up on installing them heres the link....

http://www.offroadsolutions.com/tech.html#engine

then clink on manual or automatic whichever your doing. I read the manual swap one and it's in there.

 

Only problem is that since Downey is out of business, nobody makes a long tube header for the 3.4. I keep hearing rumor about Trail-Gear making one, but I'll believe it when I see it. As for the TRD, Doug Thorley, and any other header that's advertised as CARB legal, it follows original routing over the bellhousing of the trans and drops down on the passenger side. Would probably work great, if you're swapping into a 2wd, but 4wd has extra appendages in the way.

Also, for you to get it smogged in SoCal, check out the garbage cadman had to go through to get his smogged in Orange County.

 

I've got a set of Downey headers I'm going to put on my trail rig with a 3.4 but then again everything will be routed custom for the most part anyway.

I've seen several SCd 3.4s with headers locally and they had just a little more umph to them.

:wabbit2:

 

i'm thinking about going with a set of these obx http://www.obxracingsports.com/products.php?pk=1670 and modify to fit original exhaust system. keep in mind these are stainless and will need to be tig welded and exhaust fabbed to clear everything. talked to trail gear the other day and no details yet.

 

I found this thread:

https://www.yotatech.com/forums/f160...4-swap-221917/

It looks like I might have a shot if I go with Thorley's.

 

i have read that thread before-nothing definate there.you can make anything fit. at what expense and pita? thorleys website is horrible at best it takes a while [pita] just to find 3.4 headers. http://dougthorleyheaders.com/products/productID/924 if you can the product clearly you have better eyes than me. i can however see the price clearly. thats why i am saying it looks like the obx http://www.obxracingsports.com/products.php?pk=1670 will be a better candidate to mod and install with exhaust dropping on both sides, crossover under the truck into existing single exhaust. there is also a large price difference between the two.. i guess it all depends on what you are trying to do and at what expense. i will be supercharging my engine after install and any bugs are worked out, so i want to go with headers to max out gains in performance. i also dont want to fight a crossover above the engine now or later...lol. i have heard the late model 3.4 has different manifolds ,tubular style, have not seen them . mine are the cast iron but any way you go the cross over is a problem you have to deal with.

 

I tried using the JBA headers and no go... The flanges hit on the steering shaft on drivers side... Passenger side ran across the brake and fuel lines... no bueno! You could reroute your brake and fuel lines out of the way but still have the drivers side issue.

 

which model jba do you have? t100.95 to 00runner or 01 to 04 runner.. reason i ask is the t100 jba's look similar to the obx i am thinking about trying to modify to fit. the price of the obx looks a lot better for something your gonna cut up and reweld.

 

I had the 01-04 model. I just ended up reselling them for a loss of about $100

 

I went with the Thorley 3.4 headers when I did my swap last year and they worked great. As mentioned in the referred to thread, I chose the Thorleys because they were the shortest body header which gave me plenty of room to fashion a new crossover to the driver's side and still keep everything tucked up close to the engine, including a SS flex joint, and still not hit the firewall. The driver's side header clears the steering shaft well and the power gains are very noticeable as I am running 38's on the highway with 4.88 axle gears! Just get some mandrel bent U- and J-tubes (I got mine from Summit) and take your time bringing the crossover back to the driver's side. When everything was routed correctly I then did the finish welding, pressure tested it with the ends plugged and welded up any remaining pinhole leaks. Then I had the crossover and driver's side header (which I had to mod slightly) re-ceramic coated inside and out at Jet Hot.

http://s1048.photobucket.com/albums/...20Xover%20Mod/

 

nice lookin motor Rebel!

 

x2!

Great job on the headers! I'm jealous and envious... and ready to find the same set!

 

got the part # for those by chance?

http://dougthorleyheaders.com/produc...D2/40/sfID3/39
Thorleys website shows:
THY-507-C (w/o smog fittings) - $725
&
THY-507-S-C (w/ smog fittings) - $800

And these are for 2001-2004... if that makes a difference?

*edit*

So I found the same part # on URD
http://www.urdusa.com/product_info.p..._id=1260518585

 

I got mine from URD, part # THY-507-C Thorley Header, Tacoma/4Runner 95-04 3.4L V6 no EGR. They do have the best price at $683 currently, however exactly a year ago I happened across a group buy with Gadget at URD on "another forum" that took another 10% off the TOTAL order from URD. So I ordered these headers, a couple O2 sensors, and a Competition Clutch Stage IV Clutch Kit. I'm very happy with the headers as well as the Stage IV clutch kit. I coupled this with a 38lb flywheel from LC Engineering and 1st and 2nd gears from a R151 Trans for unstoppable crawl performance!

 

Awesome truck. Thanks for sharing all the info. Very, very useful.

 

+1
clean!

 

I recently had my ghetto fabbed crossover break from heat wrapping it. I juggled buying misfit headers just to have to take them to get cut up and rewelded properly. Me having a MT I would have issues clearing the slave. So I just took it to a shop (Stan's headers in Kent, WA) and they fabbed it up for me for $600 overnight. $300 Was my quote but a stud broke off. They gurantee their work for life with free repairs. I reused the actual manifolds, but the pipes are awesome straight down to a Y collector by the front corssmember, and I do notice a difference. They told me $1200 flat to drop off the truck for a week and have them build me full custom headers. Cost was an issue, and getting it done quickly. I just wanted the exhaust fixed. But my point is, after buying headers, then paying a shop to cut them up and put them in anyway. I'd vote just having them built. It'll probably be about the same price, and much less of a headache. In my opinion you'll end up with a better quality finshed product. Not something you just dropped $700 on all cut up and put back together at additional cost. Say 5 hours min at about $100 an hour? I'm all about saving money and doing my own work, but exhaust isn't something I have machines to do. I drove my truck to the exhaust shop the first time with open pipes. The old crossover (I had the new, more difficult to work with, style) could be cut up and rewelded primitively to get you there witout catching your bay on fire, or you could trailer it. That's just what I did. Good luck!

 

You arent subject to CA smog

 

got the obx headers for 380 shipped. E-bay, look the same as thorley's to me. gonna fab up a crossover underneath.