I just ripped the factory exhaust off my 1992 f 350 dually's 460 and replaced it with a set of Heddman headers, "x" pipe, dual high flow converters, dual Dynomax super turbos and 2 1/2" pipes. Just got the truck back yesterday from the exhaust shop. At first she was very quiet and saw very little if no difference in power. After about an hour of showing it off to my buddies I noticed a MAJOR difference in both sound and power. Am I going nuts or did it just have to "break in"?

Also, It did stall while idling. My buddy and I were just talking and all of a sudden it loaded up and choked out. The check engine light used come on when coming off the highway and I noticed it came on later that night in my driveway too. I live in Rhode Island and emissions are pretty strict here so I made sure all the emissions crap was kept and re-connected.

Has any of you guys ever did a similar modification?
Has anyone ever ran into troubles after doing them?
Should I be concerned or do I just need to tweak things out a bit?

One last thing, the headers are very noisy both in and out of the cab. It sounds like an exhaust leak, you know, that "tapping" sound. You can't hear it at idle, just when you give it the gas. The exhaust shop said that it wasn't leaking just the sound of the air going through the pipes. Is he blowing smoke up my a..?

Thanks!!

 

About the exhaust leakage noise, I think he's probably blowing smoke. A couple things to consider. Fisrt the dynomax turbo mufflers are not much of a muffler for the 460. If you do much towing, don't expect them to last very long (at least that's what I hear).

Next the 460 header gaskets are "rights" and "lefts" and can easily go on backwards, creating a leaking condition, though not as bad as you would think (I learned this the stupid way). And finally, after they are run in and warmed up, you need to tighted all of the bolts, including the collector bolts. They WILL work loose through heat and vibration. If you got a set of the cheap Hedman's, you may have trouble with the thin flange getting them to seal. If you have a set of the thick flange (ie. Elite Series) they should seal up with no problems.

Typically, headers will make the engine run leaner. Depending on your setup this may be causing a problem. My truck is carb'd, so I am not familiar with the rest.

Good luck

 

Ok, took her out on the highway last night and it seems we got rid of the check engine light problem but guess what... yup got a new problem now. Before when I opened her up on the highway the trans seemed to shut down at 90 mph. Now it does it at 80 mph. So basically I got a big block that doesn't do over 80 mph so if I ever wanted to race a 4 cylinder I'd loose. I'm begining to regret ever doing this exhaust. Instead of making the truck better it's making it weaker than a ford focus......
Open to suggestions.......

 

Sounds like you have quite the situation on your hands. But I am sure it is fixable. First of all you need to cover the basics. You must ensure that you are getting enough fuel. You will want to ensure that your fuel filter is not plugging up on you, especially under load. If you are able to, put a DVOM on the O2 sensor and see what it does when you experience the problem.

You said that you had a check engine light. The code that it made may lead you to the problem eg. map sensor, tps, o2 signal, etc... You should make a point of checking this out.

You will also want to ensure that your timing is still within spec. Finally since you truck is fuel injected is is vital to the proper running of your engine that you have absolutely no exhuast leaks before the O2 sensor(s) as this will throw your fuel controll way out of wack. You should hear no popping or puffing from under the hood under load or otherwise, headers or no headers. The only header noise you may have is a ticking noise as the gas enters the header tube, and you should hear this from each cylinder at idle only.

Keep us posted!!

 

Nick,
I don't hear any noises until I put a load on her then I'm hearing what I believe to be exhaust leaks but both myself and a bud of mine already re-tightened the header bolts twice since I got her back from the shop. I just ordered a set of copper gaskets and those locking header bolts. When they come in I'm having the exhaust shop put them in. I personally replaced the o2 sensor 2 days after getting her back from the shop and it's a good thing I did because the old o2 sensor was broken.

After putting the new o2 sensor in I disconnected the batt for about a min to re-set the puter but now people are telling me to disconnect it for up to 10 min with the headlights on. What the hell do the headlights have to do with the puter????lol

 

In addition to the copper gaskets you will want to put a smear of copper RTV on both sides of the gasket surface. I am a big poopooer of excessive use of RTV but there have been many times that the only way I could get a header or stubborn manifold to seal is to use copper RTV.

Also it should only take about a minute to clear codes from your puter. This is only to discharge the capacitors, there is no huge battery in there requiring you to leave the light on for 10min.