Headers on the 5.7 Vortec

[MOBS]

You cannot get around the front O2 sensors, they control the AF ratio, the rears only monitor emissions, they can easily be deleted. AIR & EGR can also be easily deleted like the rear O2 sensors, its all emissions. Running rish can do more than just put out soot, you can also wash your cylinders if its too rich & then your in for a rebuild.

Honestly I'd say the best bet would be to order a set without any O2 sensors or emission provisions, like a race only application. Then have a exhaust shop weld (1) O2 sensor bung on each collector to monitor each bank. I have not found a single set of longtubes for these 96-97' trucks with the right O2 bungs which is kinda weird. You can get them all day long for 99'+ trucks.

Are the post-cat bungs the same thread and size as the pre-cat bungs? If so, I'd say cut out your old post-cat bungs and have them placed into your collectors.

 

[Hezsus]

You cannot get around the front O2 sensors, they control the AF ratio, the rears only monitor emissions, they can easily be deleted. AIR & EGR can also be easily deleted like the rear O2 sensors, its all emissions. Running rish can do more than just put out soot, you can also wash your cylinders if its too rich & then your in for a rebuild.

Honestly I'd say the best bet would be to order a set without any O2 sensors or emission provisions, like a race only application. Then have a exhaust shop weld (1) O2 sensor bung on each collector to monitor each bank. I have not found a single set of longtubes for these 96-97' trucks with the right O2 bungs which is kinda weird. You can get them all day long for 99'+ trucks.

If you but shorties you will not have to worry about any of this.. but then you have shorties, lt's are the way to go, the hookers or the flows just posted are the cheapest options for our trucks. I have mine setup as mentioned above, no egr, air? dono, and the rear 02's tuned out. you have to leave the front O2's in or i believe you will be stuck in limp mode.

You can buy collectors with bungs welded in already.. this is a good option. also if you dont want to get rid of egr its not hard to keep, just have to weld another bung in (steal it off the old exhaust)

 

[big_mike]

Are the post-cat bungs the same thread and size as the pre-cat bungs? If so, I'd say cut out your old post-cat bungs and have them placed into your collectors.

I do believe all the O2 sensors have the same thread pitch. But once you spend the time & effort to cut those out without damaging them you'd have been better off spending $15 on new bungs honestly.

Yea Hezsus, thats what I'm discovering, only the shorties keep the headache out of it but like you said, then your still at a minimum improvement over stock manifolds. I simply dont understand why they dont make them for the 96-98' trucks, doesnt really make sense to have a year gap like that with only shorties available.

 

[Hezsus]

There are mid available for our trucks, doug thorley tri y's sound familliar, quite expensive though..

 

[trx88]

so i get long tubes, have o2 bungs welded on the collectors for the upstream,

then do i need a cat on each side or just get rid of the downstream, and AIR and egr

so i can have long tube headers with upstream o2 sensors on each one then just straight out to mufflers and tailpipes?

 

[MOBS]

so i get long tubes, have o2 bungs welded on the collectors for the upstream,

then do i need a cat on each side or just get rid of the downstream, and AIR and egr

so i can have long tube headers with upstream o2 sensors on each one then just straight out to mufflers and tailpipes?

So long as you don't have to worry about emissions, then yep, you got it about right.

 

[bluex]

O2 sensor bungs are like $3 at my local exhaust shop, and i think that includes welding them in. As far as i know they are all M18x1.5.....

The collectors with the bungs all ready welded in are like $60 for a pair on summit. Ripoff if you ask me. The headers come with collectors, so with proper planning you could take them and have bungs put in for like $10 before you put the headers in....

 

[flyboy1294]

...then do i need a cat on each side or just get rid of the downstream, and AIR and egr...

Son of a *****, does this mean I need to send my PCM back to have the AIR tuned out also? It totally slipped my mind.

 

[flyboy1294]

Here is my write up: http://www.gmt400.com/forum/showthr...TBI-headers-on-5.7-Vortec&p=107786#post107786

 

[big_mike]

Nice write up man.