Just had my true dual exhaust done this weekend. Sounds really good. I have noticed and increase in throttle response and my truck is livelier everytime I touch the pedal! I towed a camaro and could tell I had more available power. Increased gas mileage by 1.5mgg!! I had the factory Y-pipe cut off right after the cat and resonator. I had 2.25" aluminum pipe ran with 2 steel pack mufflers and big chrome cannons exiting the sides on an angle. Sound really good. What ever you do, don't run anything bigger than 2.25" pipe on these trucks. It's a good way to loose too much backpressure. That's why alot of you guys have lost some low end grunt. 400 cubes is the breaking point on exhaust pipe size. If it is a highly done out 400 - 2.5" or bigger. If near stock(no internal improvements)- 2.25". Hope this helps.

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1999 F-250LD 4X4 XLT Supercab, Short Bed, 5.4L, AT, 3.73LS, 33"Wrangler ATS, Dual Exhaust, Custom Air Intake, Superchip, Color: Harvest Gold cc "Ready to Farm"

 

what mufflers did you get?

 

They are called steel packs. They look like glass packs, but have some sort of steel mesh or packing in them. They're suppose to last longer than regular glass packs. It sounds really good. Not too much of a ressonating sound in the cab. It is fairly loud under normal driving, but comes alive when you step on it!

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1999 F-250LD 4X4 XLT Supercab, Short Bed, 5.4L, AT, 3.73LS, 33"Wrangler ATS, Dual Exhaust, Custom Air Intake, Superchip, Color: Harvest Gold cc "Ready to Farm"

 

Actually funkster exhaust pipe diameter isnt determined by an engines displacement. The power is what gives the "need" for a certain size. There are some 400c.i engines that would make great torque with 2.25" pipes...and there are also some 350c.i engines that make 450HP and even more,which would need a dual 3" or bigger. Torky engines like smaller pipes and high HP/high revvers like bigger pipes. Its all a matter of what the engine will flow..and more HP means more flow. Bigger engines do tend to make more torque and HP..but its the design that really makes the power. Hope this helps

DS

 

I agree, that's why I said that if it is a highly done out 400 then you need the 2.5" or bigger. What you must realize is that most of the guys on here don't have done out 5.4's or 4.6's. That is why they should stay with the 2.25" pipe. Torqy motors also have to have a big enough pipe. That's why diesel trucks such as the Powerstroke come with 3" pipe from the factory.

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1999 F-250LD 4X4 XLT Supercab, Short Bed, 5.4L, AT, 3.73LS, 33"Wrangler ATS, Custom Dual Exhaust, Custom Air Intake, Superchip, Factory Step Bars, Tinted Windows, Vent Visors, Diamond Tool Box & Bed Rails, Color: Harvest Gold cc "Ready to Farm"

 

Diesal's are a whole other animal. They also have a single pipe. Your original post was about duals. As far as gasoline engines go..smaller pipes give low end torque..and bigger pipes flow higher in the revs for the horsies. Anyway,we both get the idea..haha

Take it easy
DS

 

Right on Dirt Slinger. Have a good one!

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1999 F-250LD 4X4 XLT Supercab, Short Bed, 5.4L, AT, 3.73LS, 33"Wrangler ATS, Custom Dual Exhaust, Custom Air Intake, Superchip, Factory Step Bars, Tinted Windows, Vent Visors, Diamond Tool Box & Bed Rails, Color: Harvest Gold cc "Ready to Farm"