Re: 97 sierra ext cab build
 

Well i got that answere from my other thread, looks like 1-7/8'' from the cats to the muffler, and probably the same to the manifold.

Although id really like to put headers on her, I think it would sound way better and flow better.

Re: 97 sierra ext cab build
 

No idea what size, but if I'm not mistaken the pipe diameter of my stock Y-pipe (manifolds to cat) is smaller than the pipe from the cats to muffler. Mine still has stock cats, so I don't think anything was modified there. My plan is to eventually do a little larger diameter Y-pipe tucked up higher since I'm lowered.

If you have an aftermarket intake, headers would probably benefit. I ran an Edelbrock Performer intake & Gibson stainless shorty headers (& exhaust) on my old '93. With the stock intake on my Tahoe, I'm not sure headers would benefit much. I read an article in one of the truck mags where they individually added bolts-ons, showing how performance was affected with each modification. Some parts are made to work together & could potentially do more harm than good if not used in the right manner. I'm not an engine guru though, but that's just based on what I've read/heard over the years.

Re: 97 sierra ext cab build
 

I think that makes sense, I mean just putting on headers would probably do nothing without a good intake and some good flow threw the heads. Im gonna do a bit of research....

Well, for now, I guess I can throw on a better exhaust for the manifolds back. Someone once told me if your o2 sensor was behind your cats you couldn't take them out, luckily mine are in front of the cats. I will still have to have the sensor ports welded onto the new pipe tho...

Re: 97 sierra ext cab build
 

I did find the other two o2 sensors.... So for now I put on a super 40 dual in dual out flowmaster, sounds nice, I explain better on my other thread...

Thinking about putting on the high flow cat system from flowmaster, any thoughts? Is it hard to relocate the o2 sensor? Does it make a big difference in sound and mileage?

Re: 97 sierra ext cab build
 

I have the Flowmaster cats system on my 97 and did not have to relocate the o2 sensors, they went back in the same spot... truck has better throttle response & performance and sounds way better then with the stock pipes and cats

Re: 97 sierra ext cab build
 

In the picture on the flowmaster website it shows 2 o2 sensors on one side. Is that not the case?

Re: 97 sierra ext cab build
 

Well , my 97 has 4 sensors. 2 per side , one before and one after the cat. I replaced the sensors the same time I installed the pipes. Peace of mind I guess!

Re: 97 sierra ext cab build
 

Right, the same as mine, but the picture shows two on one side, behind the passenger cat?

Re: 97 sierra ext cab build
 

One you just plug. This kit covers multiple years so sensors are in different spots

Re: 97 sierra ext cab build
 

thanks...

Re: 97 sierra ext cab build
 

Okay guys, I have questions....

What, if at all, is the possibility of modding my engine...what I mean is...Are there any BIG changes i can make. cam, throttle body, computer, heads, pistons, crank etc.... I want a good street motor and I'm wondering if it is even possible...I did a quick search for parts and cam of with almost nothing...

Re: 97 sierra ext cab build
 

Truck got new shoes today. 1984 8" Rallys painted dodge silver, GMC center caps, 275/60/15 Cooper Cobra Radial G/T's. I have the rings but at this point I feel it looks really good. Everybody else around here runs the rings and I just like being different. Also the truck has been lowered 2" in the back with the Belltech shackles.