I got a 1980 F-250 with the 400 and long tube hooker headers. it is 4x4 and i want to put dual 3" exhuast with flowmaster 50 mufflers. It has the single, side mount tank.

My question is, how do I run the driver side pipe to the passenger side without hitting the driveline, transfer case, or the gas tank? Then from there run it down to the back of the truck.

 

First, dual 3" is way too big. 2 1/4 to 2 1/2 would be a better choice. On my son's F150 4x4 we used mandrel bent pieces and fabed up the exhaust so both ran down the passenger side. I'd say get the headers installed then see how much room you have and plan accordingly.

 

Cross over either beneath the trans or right behind the transfer case. Running true duals on your is in my opinion, way to much work, especially when most true duals produce less power than a properly sized single with a good y-pipe. In your case, an added argument is your O2 sensor. Take aloof, you will see you only have one. It is intended to read the mixture from both exhaust banks. So if you run true duals, you have to either figure out how to get a good reading, or learn to live with only reading one bank and hoping everything runs right. In my opinion, the downsides do not offset the benefits.

 

The O2 sensor was non existant on any 351M/400 in general.

Is the engine stock? If so are you leaving it that way? Dual 2.25" is more than enough for the 400 in most cases unless you start getting into head work, higher compression, etc. You can always put in an H or X pipe as well.

 

The engine is semi built. Edelbrock performer cam and lifters, double roller timing chain, 4bbl intake and 650 CFM carb. Bored .030 over and new pistons. Does anyone have pictures on how to go around the trans?

 

You may still be good with dual 2.25" exhaust, 2.5" if you like. As for the trans, you may have to do a bit of digging. A few local shops would be a good place to start, tell them what you want and see what they can do.

 

Sorry, I read your post wrong, you said 1980 and for some reason I read 88. Since yours is carbed then the O2 sensor problem is not an issue. However, I would still run an x-pipe if you are convinced you want to run true duals. If it were my truck, I'd install a y-pipe, then run it as a single into a single inlet dual outlet muffler. Then I would runt he dual tailpipes wherever I wanted them to go. Less pipe, fewer bends, less weight, less friction, less thermal loss, better scavenging, more low end torque. Unless you are dumping them off short, true duals offer no real benefits for a street/daily driver.

 

My son took pics of the exhaust we did on his 4x4 truck. I need to get them from him. It turned out really well for a homemade system. If I remember right we brought both tubes along the transmission then crossed the drivers side over by the tailshaft/t-case where it is smaller.

If you do go with a shop I'd go 2 1/2 because they will crush the crap out of the tubing to get it around the trany/t-case. Same for the tail pipes. I do not recomend 2 1/4" crush bent systems because by the time they are done bending the tubing you'll be down to about 1 1/2" diameter thru the bends. keep in mind, 2 1/4" tube is reallly only 2 1/8" or less inside diameter.

Take a look at these systems. The Dynomax is NOT mandrel bent. See how small the bends are? The Hooker is mandrel bent. The pics may also help you design a system or just buy this kit and make it fit. Looks less expensive than a shop could do.

http://www.summitracing.com/parts/WLK-89016/

http://www.summitracing.com/parts/HOK-16565HKR/

 

Thanks a ton! thats what i was looking for!