If I wanna swap my 350 for a 455, where do I start?

Discussion in 'The ragtop shop' started by $100T2, May 24, 2023.

  1. $100T2

    $100T2 Active Member

    I have a 71 LeSabre convertible. I would love to swap the 350 out for a 455 because she's a big girl and could use a bit more power.

    I have no idea where to get a 50 year old 455 or where to start. Any advice?
  2. Max Damage

    Max Damage I'm thinking about it!

    You are in the right place. Let us know where you are as shipping engines isn't so easy (still doable).

    There is a parts for sale forum also.
    Matt Knutson likes this.
  3. Matt Knutson

    Matt Knutson Well-Known Member

    Start right here.

    Try to find a 455 w/T400 trans. You will also need the frame brackets / motor mounts. Some exhaust work may be needed. Trans cross member may need to move some. Driveshaft may need to be shortened. Radiator hoses may be different. Engine wiring harness will be a little different.

    Perhaps keep the 350 and put in a performance cam and tune up with a good trans shift kit - at least until the Fall/Winter.
  4. UticaGeoff

    UticaGeoff Well-Known Member

  5. Briz

    Briz Founders Club Member

    455's and big cars are made for each other. Just do it!
  6. 72STAGE1

    72STAGE1 Runnin' with the Devil

    Step 1: Find the 455 motor and tranny
    2: pull the old 350 and tranny
    3: install the 455 and tranny
    4 Enjoy the BBB experience

    But seriously, make a checklist first to get everything you need before you start to make it as painless as possible, nothing worse than waiting to find a part you need and stalling the process.
    FLGS400 and Max Damage like this.
  7. $100T2

    $100T2 Active Member

    Thanks guys. I'm in Rhode Island so I know there isn't a whole lot available locally.
  8. Max Damage

    Max Damage I'm thinking about it!

    There seem to plenty of folks in MA, so you never know.

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