First off I'm a new member, lots of great info. Got my first SD a 99 f250 v10. practically stole it. Been upgrading in my garage the last couple weeks. elc coolant, new hoses Ball joints, tie rods, all new front and back bilstein 5100s, 37 inch Goodyear mtr's. anyways I'm looking redo the exhaust has duals right now but they have ****ty welds and mismatched pipes.


I'm looking at the mbrp 4" inch stainless dual exhaust, exhaust manifold bolts are broken so I might as well do the headers and y-pipe too. where would I find those eBay headers for $200 everyone talks about? all I can find in that price range is this F 150 Pacesetter Shorty Headers 70 1326 | eBay


Is that correct?

 

If you search around here a little you will find several users who had the ebay headers fail from cracks (with some making repairs only to have them fail again). I would look to spend a little (or a lot) more $ on better headers with a Y pipe, my Banks stainless headers & Y pipe ran me $850-ish and provide noticeable performance gains from just off idle to redline, that is with the headers and Y only, the rest of the exhaust including cat is bone stock. I'm not an exhaust expert but I feel that the factory 3" mandrel bent pipe is pretty good and going to a 4" single or larger may actually reduce performance slightly, but what do I know....??

 

If you're going to replace a "****ty" exhaust job don't replace it with another " ****ty" exhaust job, cheapest isn't the best and the most expensive isn't always worth the money but the one with a good reputation is a good place to start.
As far as the exhaust size after the stock cat I don't think it makes any difference in power just noise but high flow cat or and for those who go that way no cat that's arguable. I personally can't quite wrap my head around how freer flowing headers are good for power but freer flowing exhaust after that is bad?

 

Those headers aren't even for a V10. Banks, Doug Thorley, Hedman, all have new Y pipes. JBA, Gibson, the other shorties do not but may work well with the Y pipe mod.

Single 3" or dual 2 1/4 to 2 1/2" is plenty big for a V10. It's only 415 CID. Too big exhaust actually can cause loss of flow, turbulence etc. As the exhaust cools it slows down so a smaller tail pipe keeps it moving. Moving exhaust also scavenges which helps clear the cylinders.

 

Ok so if I go with the Thorley 218y-c long tube headers it comes with a y pipe and all I would need is a catback exhaust? I'm wondering because my truck never came with a cat and it passed inspection so I guess I didn't need it? I could just use pipe as a connector correct? Borla and mbrp are both 4" I'd like to stay with duals, is flow master the only other choice?

 

dynomax has a dual cat back as well as Magnaflow I believe.