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Which to use? 3F-E or 2F exhaust manifold?

Discussion in '40- & 55-Series Tech' started by Pskhaat, Jan 14, 2004.

  1. Pskhaat


    Likes Received:
    Aug 19, 2003
    Morrison Formation
    I posted this on the 3FE board, but though I'd get some help here too:

    'm in a problematic place on the finalization of the 3FJ40:

    1. I need an exhaust system. Right now the standard 3F-E exhaust manifold(s) is/are on the head right now. The problem is that routing (actually, having to pay to have routed) two exhaust lines in the very small confined space in the 40 (one's immediately against the steering box) would possibly be prohibitivly costly. I obviously can not have flex tube as a permanent sol'n.

    2. I've thought about placing a 2F exhaust manifold there instead, that way I could utilize the existing exhaust pipe, eliminate the problems of one pipe too close. Of course having to tap in two places for the O2 sensors somewhere along the way.

    The question is then, how much $$/quality for option #1 vs. how much $$/quality for option #2. Then again, /will/ #2 even be possible? I've looked at many diagrams, etc, and I think it would be, don't however know the width of each 3F-E intake manifold vs. 2F exhaust
    manifold. Would one year of the 2F exhaust manifold fit any better against the 3F-E head than others? It appears, and can I get validation that the exhaust join at the manifold and the manifold bolt pattern were the same from 1978-1987 or was it 1981-1987?

    Any thoughts? Suggestions?
  2. Landpimp


    Likes Received:
    Mar 14, 2003
    Gig Harbor WA
    Scott, wish iI knew but SOMEONE.....help him out......as I want to hear how the 3fe is in the fj40.
  3. Poser

    Poser Oh...Durka Durka Durka. s-Moderator Supporting Vendor

    Likes Received:
    Oct 1, 2003
    How are you going to close the top of the exaust manifold that would normally be sealed up by the intake on a F or 2F? There is a guy in Mankato MN, can not remember his name for the life of me, who is running a 3FE in his 40. Runs a saginaw or scout PS conversion tho..

    Do you have PS, or are you interested in doing the swap?

    I have seen guys that know what they are doing at a exaust shop do some pretty crazy stuff with tubing, but not having a pic makes this hard to visualize. You would think that they could make something to work for you...

    Good luck!