2.5" or 3" single exhaust - that is the question.

So - I'm taking the Magnum 360 from my 02 Dakota and tossing it in my '14 JKU. The engine has a mild Comp 280 cam, stock Magnum manifolds, and I'm trying to decide whether or not to go with a single 2.5" exhaust or single 3" exhaust. I can do either, and here's the interesting part...

The Dakota with the 5.9 V8 had a factory 2.5" single exhaust...and...the '14 Wrangler JKU with the smaller 3.6 V6 also has a factory 2.5" single exhaust - same single exhaust size for both chassis'. I'm putting the 360 driveline in my Jeep...and I am VERY tempted to use the 2.5" exhaust that already in the Jeep and save myself a ton of time and $...and I can always install a bigger exhaust down the road. But...I do wonder if the 360 would benefit from a slightly larger exhaust...and why the factory didn't do a single 3" to begin with. I know it's a very subjective question, but it is interesting.

The ole rule of thumb of 'every 100 horsepower needs 1” of total pipe diameter' is ringing in the back of my mind...and while I don't know exactly how much schlitz my engine is making I know it isn't a mega power house - it might be 300 hp - maybe.

My engine will be 'done' by 4500 rpm - this is not a race Jeep I'm buildin'...

I'm thinkin' use the 2.5" exhaust and call it 'good enough'...at least for now. The Jeep already has the nice 2.5" exhaust under is and it's in good shape, and the 'smallish' exhaust might actually aid the engine in scavenging out the flow...and a whole lot less fab time which is always a bonus.

Thoughts?

- Sam