Th400 to M20, do i need a trans tunnel hump?

Discussion in 'U-shift em' started by hunter7389, Feb 24, 2019.

  1. hunter7389

    hunter7389 Well-Known Member

    Gathering parts to swap over to the 4 speed in my 69 skylark. Do I actually need a tunnel hump for clearance? My car is 100% NOT original, I dont care how "correct" it is as long as it works. Can I just trim out the opening and find a boot? No center console...
     
  2. bignastyGS

    bignastyGS Maggot pilot

    You don't actually need a shifter hump,but they really aren't that expensive to get.You will play hell locating an original,but the people who have swapped have suggest using one from an Olds. Do a search and you will find the suppliers name out.Or you can just buy a big enough universal boot and be done.My opinion,go the first route.Looks better,but it's your ride..
     
  3. hugger

    hugger Well-Known Member

    A hot wrench and a bfh will get you what you need for clearance, I can send you some dimensions and location from an original 4speed car
     
  4. CJay

    CJay Supercar owner Staff Member

    If your going to do it, do it right. An original floor shifter hump isn't that huge of an expense in the grand scheme of this. And when your done, the 4 speed will look like it was always there. I used one out of a 69 442. IIRC, it cost me $200. Plus the Fusick boot and ring.

    You gotta cut a big hole in the tunnel! You'll want to read what I did in installing a pilot bushing in an automatic crank. There are also a couple of pictures of the hole I cut

    http://www.v8buick.com/index.php?threads/pilot-bushing-saga.322757/#post-2695868
     
  5. wkillgs

    wkillgs Gold Level Contributor

  6. CJay

    CJay Supercar owner Staff Member

    I bought one of those Walt and it fit like crap. Its still sitting under my desk. It required too much metal work to make it fit decent. I guess its better than nothing though.
     
  7. hunter7389

    hunter7389 Well-Known Member

    I'm not a corner cutter, i just don't believe...for this car..that the factory way is the only "right" way. It was a 6 cyl, now 455/T400/Chevelle 12 bolt, GTO seats, aftermarket suspension and brakes. I can work with, weld and fab sheet metal with no issues, just not sure if the shifter hump is required in this case. I'm just as happy with a boot all the way to the floor panel if not. Nobody will ever get in this car and go "Thats not original"

    Thanks for the link, good information there!
     
  8. hunter7389

    hunter7389 Well-Known Member

    That would be great when you get a chance, no rush. Thank You!
     
  9. wkillgs

    wkillgs Gold Level Contributor

    Ok, good to have the feedback on how it fits the later cars. I think the opening is bigger on 68-up?
    Here's the repo in my 66. It's just sitting in there, I want to try my buddy's spot welder to attach it.

    Hunter, yeah, you could likely fab something up. The shifter bumps out towards the flat floor area. The factory hump moves the boot up higher off of the floor.
    upload_2019-2-25_11-38-54.png
     
  10. BrianTrick

    BrianTrick Brian Trick

    The Chevelle hump that all of the vendors are selling needs the opening enlarged if you are going to mount the correct style boot and ring.
     
  11. PGBuick

    PGBuick Well-Known Member

    I found the same issue when I used the 64-67 Chevelle hump. Had to cut a bunch out of it and still used bfh. One of the later humps w flat top might work very well. Clearance for the shifter body and big center bolt are the issue, along with how to effectively boot the hole.
     

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