Turbine Doc
Just Another Diesel Guy
Just wait that cat is a POS, and not needed for the 6.5, which was a feel good measure only to appease politicos that haven't a clue, the cat on the 6.5 was borrowed tech from gasser world, except they forgot Diesels don't get hot like gasser and the soot just collects and blocks the core over time, making the vehicle run worse and more polluting over time than if they had just left it off, technology just hadn't caught up yet for the 6.5 era Diesel to be "clean".
If the traps made a difference then the (S/L56/EGR) would not have the exact same opacity test spec as the (F/L65/non-EGR).
Exhaust is an essential upgrade, even in a people hauler, helps keep the coolant temps of engine down especially as cat becomes plugged up, power upgrade, longevity upgrade and slight mpg improvement. If me I'd remove the stock, run the 3", save the stock one for when the aftermarket one had issues.
I suspect the 3:62 final was a special order these normally came with 3:73 or 4:10 on 4x4 , my non EGR C1500 F engine burb with 3:42 has plenty towing power you should be fine.
Had that been a USA truck most probably there would be no EGR engine in it, since you say it's a K2500, is it 6 lug or 8 lugged wheels ?
Many Canada bound/built and vehicles built to be sold in states like the peoples republic of Kalifornia mandated the addition of the EGR stuff, even though it took until the advent of modern common rail Diesel with DPF & Urea to have anything more than visible reductions from the tailpipe.
This despite the situation that it takes almost 2x the fuel as it once did to get down the road, mpg has really suffered in the newer DPF'd trucks with quest for "clean" exhaust, so IMO jury is still out whether or not we really solved anything with smog equipment on a Diesel, seems to me burning more fuel overall is just as bad as "sooty" emissions without DPFs or soot traps.
As far as PCM goes, it has to be reflashed in the OBD-II, adding a TM only for your truck won't do as much for you, as you'll need to fake out the PCM since you are a EGR equipped vehicle, PM me and we can discuss some things, as I'm not sure if what works on a S EGR vehicle, works on a F EGR'd vehicle.
You said you wanted longevity out of it, how do you plan on using it, as tow vehicle or a people hauler/daily driver,
I'd suggest a bypass oil filtration system, fuel pre-filters, and a few other things, which don't have to be done all at once, it took me about 2 years to get to my reliability comfort zone.
I'm still reaching for more power, I just rolled 200K on mile last month so I'm backing away from the quest for power for now until I install my new engine in it in when I get back to Ms this fall.
