I have a 1999 F-250 V10. I have stock pipes on it. What do you suggest I do to exhaust to get better air flow for better mpg? What is the cost?

 

Moved to appropriate forum

 

well first off I would get a aftermarket y-pipe do a search for ypipe under the v10 forum, I added one to my 2000 excursion 4x4 v10 and gained 1.6 mpg and it sounds alot better. My next suggestion would be a flowmaster 70 series they appear to sound the best on the v10 engine as it has 70 degrees of firing compared to the v8 engines that are 90 degrees. You will probably never get the v8 muscle car sound if that is something you are looking for. But the best gains are seen from the ypipe in my opinion. As far as headers go I have not looked at them much for the v10, however I put some edelbrock on my f150 and it did not make a big difference at all.

 

You have a '99 truck without the necked down y-pipe. You dont need this. You wont gain anything by adding it.

I also have a FM 70. I like it and it sounds nice. Very little drone.

Ebay headers are the poo if you ask me. I put a set on my '99 V10 and have enjoyed them since. Idle sounds different and I can feel a little more "seat-o-the-pants" power. Well worth the $125 IMHO. They are copies of JBA cat-4-ward headers, minus the fire -cap -dome(whatever) thingy.

Keep your stock pipe, don't buy a cat back system as you already have mandrel bent 3" aluminized pipe from the factory. A high-flow cat helps a little too.

 

This hasn't been proven....yet. We're all waiting for Mike aka "Mr. 5-Star Tuning" to dyno his 99 before and after.

https://www.ford-trucks.com/forums/8...-and-cost.html