Whipped383

How much do headers help the 8.1? Witch ones are the best? Do you have any issues with leaks or melting things? My truck is a tow rig and it needs some help currently is bone stock

TIMINATOR

See my post about the crossover and header install. We have a complete shop with a lift and our install with all of the glitches and phone calls took about 10-12 hours. Check to see if your rig has pre cats, that glitch will add some additional time (hours) to the install. Upon recipt of the headers, check to see if the O2 sender extensions are correct, ours were close but wouldn't work. Get the required gaskets FIRST, some of them may be hard to find. We added some length to the O2 senders and soldered it all together and insulated everything with heat shrink tubing. Shop around a lot for best pricing! Your results may vary. TIMINATOR

Whipped383

No pre cats on mine. Have a pipe bender hag me shop to to do any needed exhaust work. 10 hours sounds retarded to to put a set on

TIMINATOR

Trust me, that's not what we expected either. We are all trained, seasoned professionals here and although nothing was difficult, there was an inordinate amount of small, time consuming B.S. that we had to contend with. The time includes actual work (in man hours) and phone time to the factory twice, phone time finding the correct gaskets (header, EGR feed, and tailpipe flange), removing the pre cats, welding on extensions to make up the difference for the pre cats removal due to the fact that both pre cats were nearly in the middle of where the down pipes needed to be cut, splicing and soldering all eight of the O2 sensor wires, r & r of the steering shaft, loosening and moving the engine to the passenger side to clear the steering shaft, loosely installing the header bolts to ensure that everything would fit, then discovering that all of the header bolts had to be removed and have washers (2 each) installed under their heads because the metric bolts supplied in the kit were too long among other things. Your truck may not have the pre cats, or the EGR tube where mine was, and you now know about the bolt, possible O2 sensor extension, and gasket issues before you start your installation. I didn't post to show how incompetent we are, but to give an honest report of the installation process since it didn't go according to plan. You may not care, but the next guy that may try to put his headers on tonight, and need his truck in the morning to get to work may care. Moral of the story: check to make sure the O2 extension plugs are correct, buy the gaskets before hand, and don't plan on doing this in a few hours. It just may not go according to plan. TIMINATOR

d-bo71

So what other company makes headers for us 8.1 owners? what kind of power is on the table by adding headers?

Whipped383

How much did the headers help? Do you have pics? How bad was the interference with the steering shaft? Did you have to use angle plug boots or do the factory straight ones work with the heat shields?

My biggest fear is leaks and melting things. With it being my tow vehicle its gonna get really hot. Heck with stock exhaust the plastic retainer that holds the clip in place on the trans cooler fitting is melted. How hot must these things run?

Raylar Engineering

You'll want to look up JBA and Gibson for shorty headers which are smog legal. Those typically bolt to factory collectors which makes the install very quick. If you don't care about passing visual smog inspections, Stainless works makes a really nice set of long tubes.

You'll see a good boost in performance from headers when the engine is tuned. Shorties are typically about 15-20hp and long tubes closer to 25-30hp. Leaks are minimized (if ever) if you use the factory stainless steel gaskets, though any big block chevy exhaust gasket will work. Headers can torch spark plug boots, if it happens, you'll want a set of spark plug wires with ceramic boots - the problem will go away forever.

TIMINATOR

Stock boots and wires, the tubes cleared the steering shaft by loosening up the engine mounts and pry barring the engine towards the passenger side. Biggest problem is the lack of gaskets, and buy some small diameter AN pattern washers to put under the bolt heads, or cut about 2 threads off of each bolt. You need two washers for each bolt, 32 total. After the first trip, about 4 miles, the headers were a nice blue/plum color, so yes they run hot, I also have a chip in it too. The headers helped a lot, but then again the pre cats only flow about 300 cfm each @ 28". How much gain was from the headers? Can't say, but the biggest deal to me is the Allison doesn't drop down 2 gears every time you lean on the gas, then upshift after a time. It stays in 5th pretty much all the time over 40+ mph unless you are accelerating more than normal. Heck, mine at 65 when you bump up the speed with the cruise button would drop into 4th, then shift back up. Quite annoying for an engine of that size. The chip helped that some, but not as much as the headers. Regarding the shortys, don't even bother for any towing or intended performance usage. The flange from the manifolds is 2 1/2" and the headpipe is that size down for 8" or so, then it necks up to 3" all the way back. That bottleneck, plus the lack of resonance/tuning only gives a bit of restriction improvement, not a fully tuned header. Stainless works is the only game in town for long tubes, BUT, the exhaust flange is the same as any BB Chevy. If I would have had more time than money, I would have taken measurements and pics, and ordered the closest existing design that would work with the least work. Then I would post here what I discovered. The main difference is these trucks use a torsion bar instead of a spring, make sure you allow for that. Buy some swap meet used headers until you find something close. You can buy a lot of used truck headers for $920.00!!!!! So mebbie you have to get a "U" bend or two, to make mods but that's still cheaper... Since I never received a call back from the header company, I wonder if they have any intention of taking care of the existing problems with the product. You have no idea how much it pisses me off to hear "we have sold hundereds of those and yours is the first complaint." Then I ask: "is there somebody that's more familiar with this application?" and get told there is no one else to talk to. Maybe mine is the ONLY 2002 GMC 2500 HD short bed, extended cab truck that has pre cats, that the (head flanges (2), EGR feed tube, and rear tailpipe) gaskets were missing, and had a different O2 sensor plug style, required stepped wrap around clamps, AND had shallower tapped bolt holes in both heads. If they call back or return the E-mails we sent Thursday, I'll post that too. Otherwise plan on spending even more cash(the high temp header gaskets, EGR feed gasket and rear flange tube gasket cost me $45.64 and I has the Stainless AN washers here from another project) and time on your project. You will need a welder and some(under 2 feet)of 3" heavy wall tubing if you have pre cats. Gas mileage also improved as well as did the throttle response, but remember my pre cats were very restrictive, and I did my Throttle body and air box mods at the same time. TIMINATOR

Whipped383

No pre cats on mine. Like I said I do have an exhaust bender. I'm considering building new lead pipes so I don't have to hack the factory ones. I'll have to find a flange for the one side to do that. I'm considering using v band clamps for the collectors. I have efilive to tune with I'll just need to install a wideband.

d-bo71

Hey I found some options from summit racing long tubes and shorties from JBA for our 8.1 anywhere from 200-400 less than what these SW go for. Almost 1k for headers is outrageous for what we are going to use them for. I'm going to keep looking as this will be my next mod before I efilive.