1. Welcome To GMTruckClub.com!

    The #1 Chevy Truck Forum Online
    Online since 2004, we are the #1 Chevy Truck & SUV forum and user community. If you have any questions about your Chevy or GMC Truck, SUV or Crossover, or just want to connect with other GM owners and enthusiasts around the world, you've found the best place on the internet to do that.

    Join Today ~ It's Free
    Registering is Free and Easy! Hope to see you on the forums soon!

Size does matter

Discussion in 'Performance & Fuel' started by sheep, Dec 29, 2008.

  1. sheep

    sheep New Member

    maybe im just not looking or searching in the right area but i cant seem to figure it out

    i just need to know whats a good exhaust cat-back size for the 5.7? i like to go a little bigger then stock but of coarse i dont want to free it up too much, it will be exiting the stock area so it will be a single out.

    thanks for any help
  2. retired2001

    retired2001 New Member 1000 Posts

    I went with 2.5" on the '96 I had. I had true dual Flowmasters installed and it worked for me. good luck!
  3. scooby2b2

    scooby2b2 New Member

    Size Matters

    My freind went with a 2.5 dual in single 2.5 out flowmaster and 3.0 pipe out stock location and hangers. Good sound not too loud but not queit either. Ran better and a local muffler shop installed for 170.00
  4. cascott325

    cascott325 New Member 1000 Posts

    sorry to cut in with my own questions, but if i can add to this topic it might help both of us. i priced some exhaust shops for custom dual exhaust and this is what i got from them,

    - i asked if high flown cats helped, he said not really except for actual performance vehicles

    - i asked if an 'H' pipe would help with torque, he said yes but to enough to compensate for the price

    - i asked about 1 2-in-2-out muffler or 2 1-in-1-out mufflers, he said that instead of having an 'H' pipe, the 2-in-2-out would act as if there were an 'H' pipe and that if i had 2 1-in-1-out that the sound would pop and crackle (like the cleshe' redneck sound) whereas if there were a 2-in-2-out, it wouldnt.

    - he also stated that the highflow cats could and probably would cause the O2 sensors to throw a downstream code or something of the sort


    i cant really remember what else was discussed, but i was wondering if any of this has been experienced or experimented with and am asking for some feed back please.
  5. sheep

    sheep New Member


    i have a highflow cat on my tercel and 02 sensors seems to be fine

    ill probably go with a 3" pipe, its not going to be duel so i think 3" would be ok for the single
  6. ct9a

    ct9a New Member 1000 Posts

    3" is fine for a single, that's what I went with on mine. I also have the high flow cats and an aero turbine muffler and it sounds and performs great.
  7. sheep

    sheep New Member

    i was going to get a price on 1 into 2 and have the tips come out at the corners of the rear bumpers but i dont think i want to go that rout anymore. we shall see
  8. cascott325

    cascott325 New Member 1000 Posts

    i got a price for mine the other day. for 2 magnaflow high flow catalytic converters ($80 a piece) the muffler, 2 1/2'' tubing from the headers, total cost of around $400.
    the muffler is a flow master 2in 2out, and like sheep said, my tips are coming out at an angle towards the rear corners. i cant wait
  9. sheep

    sheep New Member


    im sure they will look and sound awesome. everyone does it straight out the back and imo its really ugly. i also considered coming out right before the rear tires but i think thats a little too redneck for me
  10. tlperry68

    tlperry68 New Member 1000 Posts

    You can't go wrong with 2.5" flowmasters.

Share This Page