350 open header truth from rumors

Discussion in 'Performance & Fuel' started by SPW94, Sep 25, 2011.

  1. SPW94

    SPW94 New Member

    so i have a 89 Chevy with a 350 in, i would like to run open headers in it. first id like to know.... Ive searched else where that lose or back pressure=bad and others saying no back pressure is good. also will it get me better gas mileage? anything else i need to know before doing this? thanks
  2. Rockstarrchevy81

    Rockstarrchevy81 Rockstar 3 Years ROTM Winner 1000 Posts

    Open headers will make your truck have lag which is loss of back pressure. The back pressure can be good and bad in both ways too much back pressure can rob you of hp and torque and too less back pressure will generally do the same thing. It also depends on what all you have done to your truck and everything also.
  3. Greg84

    Greg84 Rockstar 100 Posts

    In a perfect world.. yes, less backpressure would give you more power. However, your truck assuming its stock has the swirl port heads which aren't very good for performance to begin with, so you're not going to gain much by switching from the stock manifolds to headers, and the gains going from headers connected to an exhaust system vs. open headers are going to be even less if any at all. If you had a high compression motor with some fancy high flowing AFR heads and a big cam, you'd see some gains. A stock late 80's TBI engine, not so much.

    The only thing you can guarantee with open headers is you'll have pissed off neighbors, occasional stops by the local law enforcement, and ringing ears after every 10 minute drive.
  4. Rockstarrchevy81

    Rockstarrchevy81 Rockstar 3 Years ROTM Winner 1000 Posts

    Yeah i totally agree man! My buddy has a 80 something model F 150 single cab short wheel base with 302 bored with open headers and exhaust cut under the cab and his truck was slow as hell and had allot of lag but was too damn loud to be driving on the road lol!

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