3-Speed Saginaw Bellhousing

Discussion in 'Transmission & Driveline Topics' started by Jeremy King, Nov 20, 2017.

  1. Jeremy King

    Jeremy King New Member

    3
    0
    Nov 20, 2017
    Hello,
    My name is Jeremy King and this is my first post.
    I’ve had a 1973 SBC 400 sitting is my garage for about 25 years and finally got around to rebuilding it. When I was finished, I went in search of something to put it in. I found a 1980 Camaro with an excellent body and solid chassis. The 229 V6 that was in it was running but not very well. It seemed like the perfect car for my project. I’ve done many SBC swaps and rebuilds over the years but, until now, my experience with transmissions has been mostly limited to the TH350, TH400, and a couple of PowerGlides. I have replaced a few clutches but always in factory correct cars so I’ve never had any problems.

    Here’s the problem I’m having now: this Camaro has a 3-speed Saginaw manual and the bellhousing is too small to fit over the 168-tooth flywheel on the 400 small block. Like I said, I don’t have much experience with manual transmissions and didn’t know there were different sizes of bellhousings. I’ve done some research and it looks like the GM 621 bellhousing is what I need but before I spend the money on it, I want to be sure I’m not going to run into any more issues and I have some questions.

    Are all Chevy 4-bolt manual transmission mounting patterns the same? Will the GM 621 bellhousing have the same depth as the current one? Will the clutch fork be in exactly the same position and work with the existing clutch pedal linkage? Will the SBC 400 starter fit properly in this bellhousing? If I install the GM 621 bellhousing, are there any issues I may run into other than the questions I’ve already asked?

    I realize that the 3-speed Saginaw, the 2.73 rear end gear, and the SBC 400 are not the best combination for this car but I will deal with that sometime in the future. For now, I just need to get this Camaro back in drivable condition. Thanks for any advice you can offer.
     
  2. LADDTWZ

    LADDTWZ Veteran Member

    555
    24
    Aug 11, 2012
    Schoolcraft, Michigan
    I did the exact same thing. V6 229 w/ sag 3 speed. Found a 621 and used it when I went to a SBC. Now I did go with a Sag 4 speed but everything bolted up just fine.

    And BTW Welcome to the Nasty. Great, great group of people here with a ton of knowledge.
     
  3. black_aerocoupe

    black_aerocoupe Veteran Member

    Depending on what you have, starter, flywheel, balance plate, clutch, and possibly redrilled get the block for the starter pattern, and you can have a 153 tooth setup. Helpful if you go with an LT1 T56, possibly header clearance if you get a nice late model starter.

    The bellhousing and staying 168 is the easier option in your case, I am pretty sure. Be careful to get the right fork. And way to keep your eyes on the end goal. Project creep is an evil mistress.
     
  4. greencamaro1981

    greencamaro1981 Veteran Member

    590
    0
    Jun 2, 2010
    Montana
    621 bell housings came in all trucks get one from a 70s chevy and it will allow everything to bolt in corectly, and the 3 speed saginaw, 4 speed saginaw and muncie all share the same lentgh
     
  5. LADDTWZ

    LADDTWZ Veteran Member

    555
    24
    Aug 11, 2012
    Schoolcraft, Michigan
    Somewhere I have a 5 bolt bellhousing that came of a old truck. Paired with a sag 4 speed that's in storage somewhere around here if your interested. Cheap ! PM me if you like.
     
  6. Jeremy King

    Jeremy King New Member

    3
    0
    Nov 20, 2017
    Thank you to everyone for your responses. I will get a 621 bellhousing and post a pic when I get it all put together.
     

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