I have an ’03 4x QC 4.7 Dakota and am looking for an extra 15 to 30 horsepower. So far, I have only added a TrueFlow intake system that I have slightly modified. I removed the tube going from the wheel well into the airbox, and removed the large rubber piece from between the radiator and the right headlight. It has increased performance a little bit, does nothing for milage, and sounds cool. That’s all I’m asking for. So on to the exhaust. From a performance standpoint only, which should I expect to be a better investment.
1. 3” high-flow cat going into a 3” single inlet 2.5” dual outlet Magnaflow
2. Same as above but with 2.5” cat and inlet on the muffler
3. A 2.5” single to dual Magnaflow only
While I’m on the subject, what does the length of the muffler affect, anything? I’ve heard the newer trucks have some strange factory setups that can include multiple cats, is this correct for the ’03 model? Sound is second to performance in this case, though I hear the Magnaflows do sound great. Will any of the above options actually decrease performance? If anyone was wondering I want two polished tips exiting just ahead of the rear passenger tire, I don’t mind the extra cleaning, I think it will look cool. Lastly, I’m trying to gain my 15-30 for under $500, already spent $200 on the TrueFlow. Am I asking too much?

Thank you all for any input

Tim

 

3" might be a touch big, dual 2.5" is definately going to be on the big side. You'll actually lose power in lower RPMs versus a properly sized setup. I'd recommend 2.25 into a 3" cat and 3" muffler out the stock location, unless you could find 2.75" stuff.