Been a while since I started a thread Ina section other then classifieds....
Anyways, I'm getting rid of the crappy stock exhaust on my 97 sierra z71, thorley tri y's will have to wait until I can find some... For now, I'm ditching everything past the manifolds and going with the headpipes back from the 3/4 ton trucks which are 2 3/4" diameter-they look like sewer pipes compared to the puny stock 1 7/8" half ton pipes... Just bought a spintech pro street 6000 with dual in/out 2.5". My questions is, has anybody run an x/h pipe on these trucks? Any vids/sound clips? My exhaust will be dumped either before or after the rear axle depending on length of x/h pipe. The one vid I used to base my muffler decision on YouTube was from a 99 Tahoe which had the exhaust exiting in stock location. I know mine will be a lot different, but can anybody chime in with their opinions/experience with this?

 

Nobody with experience with this on an l31? Anyone done it on an LS truck?

 

I have a H pipe with mine its a dynomax intermediate pipe

 

Did you notice a difference performance or sound wise? Are your edlebrock headers smog legal in Cali? Do they still make them? Shorties, mid lengths or long tubes?

 

Anybody else ever do this? You out there 6789olds?

 

STock Magnaflow replacement, notice teh nice mandrel bends.


Walker front part of a 3/4 ton exhaust



matching rear part





1/2 ton vs 3/4 ton L31 exhaust




Getting rid of the stock headpipes is a great thing to do. I run Hooker 2462 1hkr which are ceramic coated 1 5/8 x 2 1/2" headers with dual 2 1/2" exhaust into dual 4" pipes out the side b4 the rear wheel on teh passenger side.

These are the Hedman Huslter series headerrs



Most shorties are legal, some mids are, such as The Other Guys (TOG)Headers. LT's arent Cali legal for the most part.

headers/exhaust/tune(mild tune only leaned PE mode multiplier-stock timing) totally made my truck accelerte differently felt like I dumped a 383 under the hood.

On teh L31 its tough to properly install an x or H pipe as the length of pipe before the x or h cant be equal for both banks. Unless you can run the exhaust straight back on both side of teh trans, I owuld skip the crossover pipes.
they do add low-mid rpm torque though, and quiet down the noise a bit.

peace
Hog

 

I know about the 3/4 ton headpipes I've got those waiting to get installed with the spin tech muffler. Been looking for thorley tri y's for my truck but they're not made anymore so they're really hard to find... I need to be able to pass smog

 

I have shorties I got them used and had them ceramic coated . Not sure if they make them anymore . Long tubes are better but I am in cali to so I did the shorties . I notices a big difference in power with my exhaust but I did the headers h pipe and tune all at the same time tho .

 

Any increase in gas mileage?

 

Yes I went from average 13 mpg to 16-17 but then I did the stall and went back down to 13-14 ave . On a high way trip I can get 18 keepin it under 65 and flat no hills .