I have the 99 f150 4.6L V8 4X4, Airaid intake, granatelli tuned MAF, Edge Evo tuner.

I just did a stainless 2.5" true dual Exhaust, Xpiped with two 11" Magnaflow 2.5" SI/S, with the tips 45 degrees behind the rear tires..

Iv read that these will break in and become louder? if so how long?

I orderd my JBA ceramic shorty headers will this make it louder or should i change to magnaflow high flow cats?

 

I would go with the high flows, and it should take about 1,000 miles for the muffler to brake in, I think.

 

Trade the 11's out for some magnapacks, swap out the OEM cats for some hi-flows, and cancel the order for the shorties and get some long tube's and it should be loud enough!

 

x2 on that!

 

As for my headers they show up tomorw cant cancel.... any idea wat my options are for cat? i was thinking of deleting the rear cat and doing magnaflow primaries? any idea wat the part # is?

 

Delete all the OEM cats for just 2 Magnaflow hi-flows, Darren will chime in with the part number. I guess the shorties will have to do, anything is better then the stockers. FYI this setup will make your truck sound damn near like a Mustang GT, so just a heads up.

 

part # for the maggies is in my sig, they will make it quite a bit louder

 

Delete your rear cats and replace with pipe, and after a couple thousand miles you'll be at my sound level.

 

So im gona delete the rear cats, should i bother changing out the stock front cats ? would i run into any O2 sensor isues?

 

You shouldn't but if you do get a CEL its easy to fix. Your rear O2 sensor should be after your rear cat, if its mounted in it like some models have it, you will need to re-mount it in the pipe, then do the O2 mod.

 

sounds simple enough, does anyone have pics, or a how to link?

any idea wat the part number is for the front cat?

 

https://www.f150online.com/forums/ex...rear-cats.html

and 91076 are the replacement front cats.

 

Sell the shorties, get hi flows, long tube headers, scratch those maggie 11s and get glassspacks.. That'd be tight!