For those that don't know I eliminated the y pipe in my 08 F350 with the 5.4. I installed a H pipe and dual flowmaster super 44. Power is amazing now and I gained an average of 2 mpg. The truck would never spin the tires before and now it will smoke them off the rim. I also went from 9.33 0-60 times to 7.81 seconds.

I finally got to test the truck while towing after getting the new exhaust. For those that followed my new exhaust thread and for everyone that messaged me about it I know you had questioned its low end torque while towing with the free flowing exhaust but until yesterday I haven't tested it. I got to tow about 5500# and it did much better then before. Big increase in usable power while towing and mpg. Traveled about 4 hours, 2 with empty trailer and 2 with a car on it. Also spent about 45 minutes idling too so my numbers are a little low due to that. Got 11.5 mpg empty and ended up at 10 mpg by the time I got home. Having towed similar loads a lot before I can say that's about 1/2-1 mpg better. To me efficiency is the ultimate proof of power gains so I can now say the exhaust was a total success

 

This is something I am definitely interested in doing to my 09 f250 with the 5.4. Have to look up your earlier post on where u came up with the h pipe.

 

I have been dreaming of doing this setup since I bought the truck new. I have done 3 other exhausts before this and never pulled the trigger because of the unknow. I can now say with confidence that it was the best mod I have done.

 

I would like to know if it will work on my 2004 2valve 5.4? Ive been missing my dual exhaust and im gonna add something again this summer. If the hpipe will help ill run that in, wonder how it will work the the 2valves have a single cat and not two one at each exhaust manifold???

 

I imagine it would work fine. You can always redue your down pipes to add cats back in and run 2 instead of 1

 

I was looking at your pic and it looks like i can buy two high flow mini cats and weld them on each side behind the oxygen sensors and then make the drivers side 90* across the trans and run duals to where the tcase skid plate is and have the h-pioe right there and then run it out like normal. If it doesnt rin tomorrow im gonna take some measurements and see what size cats i can find

 

Sorry haven't been on in a while. From what I have read and been told by my exhaust guy is that the stock cats flow very well and there is no real benefit to removing them.

 

Unfortunately, the 99-04 models only have a single 3" converter instead of the dual setup on your 08.

Why does your sig say that you sold your 08 F350?