Your correct, stock is 2.25 and the 2.5 is plenty anything more could constitute a performance problem if your not putting big whp down and shoving crazy amounts of exhaust down the pipes.

 

I figure too, it will be hard enough to get the 2.5 inch in due to the rear bank clearance anyway.

 

Matt, definitely look into that more and let us know what you find out. I'm curious to see what some pros have to say.

 

It depends on your performance mods you have added to the Deuce 2.5 is probably you limit if you mostly stock. You need a little back pressure.

 

Just a Lew tune, 2.5" Magna Flow Cat backs, K&N, I don't really think the ram air hood amounts to much of a performance mod.

 

2.5 is perfect

 

Tadd, do you know how much horsepower yours is pushing currently? Curious if you have exact numbers (had it dyno'd) or if you can estimate it.

 

I don't know for sure Matt never had her dyn'd


Had people tell ne anywhere from 350 to 400 HSP but that is just a guess

 

Never heard of that, source of info?

Stock LS4 is 2.5"

3" is perfect lol

If you've already invested in a 2.5" Magnaflow cat-back to replace your 2.5" factory cat-back, I understand your dilemma. My recommendation to those looking to upgrade their factory system is to go 3" with a 3" downpipe, and if you're doing headers certainly then to step up to 3".

 

The Source was the Thorley sales person

My magna flows are bigger than my stock exhaust and they are 2.5 inches

Could swear the stock ones where 2.25
I would not have ripped out the stock exhaust to replace it with one the same size

Any rate the Thorleys are 2.5" and the magna flows are 2.5

So is it is too much cash involved to change out now