Hi Everyone,

In reading through past articles, it appears that the Magnaflow catback kit does actually give a small boost to torque and hp due to flow engineering. However, Magnaflow appears to only sell a 3" for the Expy's. Is this the kit? These same posts have mentioned that a 3" exhaust is too big and causes a loss of low end torque. Any help/opinions greatly appreciated!

 

On this page http://shop.ivalueinternet.com/bigex...uct_id/638.htm
it looks like all the cat back systems for the Expy and f150 are all 3". Notice also that the tail pipe for both is the same number. You can probably install the single in duel out from the f150 if you want. Also if you measure the length of the muffler you currently have you can probably just splice in the new muffler. Stock tail pipe size is 2 1/2 inches.
BTW, I just installed the 2 1/2 SI/DO using the universal tail pipes on this page. I also used muffler #14218 from herehttp://shop.ivalueinternet.com/bigex...duct_id/16.htm

 

So is the muffler the restriction (i.e. swapping the muffler is where the small torque boost will come from)?

Sweet truck, BTW!!

 

I used the Expy 22" long muffler 3" but had 2.5" pipe used (mostly to try and keep the sound level a little lower).
I have really liked it.

 

The stock muffler is a chamber style so the strait thru design of the magnaflow should help with performance. It will sound better too.

 

Great! Thanks for the input!