Exhaust questions

Hello I’m having shop install new engine on my 05 4.0 and was gonna have them put new exhaust manifolds since they’re already gonna be in there. Ordered some DT long tubes. But having some regrets as far as if it’ll pass emissions.

what can I do for it pass?
Also, how many studs and nuts do I need for the gaskets? Can’t find a correct part number. Thank you.

 

What part of the country are you in? If you’re in a large metropolitan area where there is emissions testing, then the long tubes definitely wont pass. They will also throw a check engine light and codes p0420 and p0430. You might be able to get rid of the CEL/codes with HPtuners or if you can find some discontinued URD o2 simulators, but it still wont pass emissions. If you live out in the country then you will likely only need to worry about dealing with the CEL/codes

 

I used ARP LS1 header studs on mine. Part number 434-1301. They are stainless steel but require a thread chaser to clean out the holes.

https://www.4runners.com/threads/2006-v6-sr5-build.34720/#post-524039

 

Why set yourself up for headaches? Even if you can get it to pass emissions, headers will increase underhood temperatures significantly which can cause a littony of problems. Although they aren't guaranteed to leak keeping them leak free for any length of time can prove to be a challenge. The improvement in performance will be negligible unless there are significant modifications to the valve train, induction, etc.

 

Not worth it