455 and a 4 speed in a 1966 Special

Discussion in 'Street/strip 400/430/455' started by Dragnknights, Mar 29, 2021.

  1. Dragnknights

    Dragnknights Active Member

    Has anyone attempted or done this?
    To make long story short:
    The car is originally a 300cui 3 on the tree car
    I put a 4 speed floor shift in it and started building
    a 455 for it.
    Bought the TA performance Frame Pads and TA performance Headers and tried to install the 455, but it was a mess. The 455 hits like everything Firewall clearance issue, header to cross member clearance issue, the Z bar is an issue etc. I called TA performance, and they were great, but basically said "every car is a little different" and basically, your results may vary.

    So I guess I'm just curious if anyone has done a swap like this?
     
  2. Super Bald Menace

    Super Bald Menace Frame off oil changes

    You're using the wrong set of holes on the block if the 455 is hitting the firewall. The motor mounts fit into different positions depending on which series car it's going in. You want to use the rear set of holes
     
  3. Super Bald Menace

    Super Bald Menace Frame off oil changes

    I put a 455 and manual trans in a 65 Special that came with a V6 and 3 on the tree. I used all of the V6 manual shift components including the bellhousing. the problem you're going to run into is the headers. They are not made to clear the manual transmission components in that particular chassis.

    Here is a picture of my 455 mocked up in my 66 special frame on my current project. Exhaust manifolds leave all kinds of room but headers not so much.

    20201202_165424.jpg 20201220_150319.jpg 20201202_165424.jpg 20201220_150319.jpg 20201202_165431.jpg
     
    Last edited: Mar 29, 2021
  4. hugger

    hugger Well-Known Member

    Ive done several

    It does but close to the firewall,..you will need the 67 GS400 heater core as it is angled

    The steering shaft will be really close,.. clearance the header there

    The brake line from one wheel to the other will need to be repositioned

    Brake booster clearance is really tight if using aftermarket covers

    Header collector clearance is an issue on all 4speed th350 setups,...cross member mods or a custom piece are needed
     
  5. hugger

    hugger Well-Known Member

    Removing the casting lugs off the block make life easier also
     
    docgsx likes this.
  6. Bigpig455

    Bigpig455 Fastest of the slow....

    x2 - I will never leave them on any future builds
     
  7. NZ GS 400

    NZ GS 400 Gold Level Contributor

    Ethan, just curious how did you run the wheel to wheel brake line? I need to do that on my car. Thanks
     
  8. Super Bald Menace

    Super Bald Menace Frame off oil changes

    Here is how I ran the brake line
    20201025_141847.jpg
     
  9. NZ GS 400

    NZ GS 400 Gold Level Contributor

    Thanks for the picture. That looks great.
     
    Super Bald Menace likes this.
  10. Dragnknights

    Dragnknights Active Member

    Great Pics! Thank you for the feedback. It's much appreciated and gives me a good jumping off point on that to expect!
     
  11. Dragnknights

    Dragnknights Active Member

    Great info,
    Again. Thank you so much. I was starting to get a little frustrated with it, and there isn't a whole lot of information out there on this swap
     
  12. B-rock

    B-rock Well-Known Member

    The headers are a pain to install on the early skylarks. I had to dent mine all over. Upper tube control arms helped out a ton. Also ground down a special wrench to fit the bolts better.
     
    Super Bald Menace likes this.
  13. 12lives

    12lives Control the controllable, let the rest go

    Which one/where? Picture?
     
  14. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    Block2.jpg
    BlockLug.jpg

    One at front and rear of the block on each side.
     
  15. rhedelius

    rhedelius Well-Known Member

    Thanks for starting this thread Dragnknights and thank you to Super Bald Menace and Hugger for some great info. If all goes well, I'm planning a similar swap with a 430 into my 66 Skylark (auto trans).

    Does anyone have the part # for the 67 GS400 heater core with AC? (or a sister car that uses the same one?) I tried looking on Rock Auto but nothing is listed for a 67 GS400. It lists one for my 66 with the 300 but that's what's already in the car and doesn't have the angled tube. Other places show one for 68/69 but not 67. Was it a 1 year only thing?
     
  16. Super Bald Menace

    Super Bald Menace Frame off oil changes

    Honestly, all the times I've done this swap I've used a regular heater core including in my current 66 Special which is getting a 455.
    20210409_164309.jpg
     
    Quick Buick and B-rock like this.
  17. rhedelius

    rhedelius Well-Known Member

    Good to know, thanks for the update!
     
  18. hugger

    hugger Well-Known Member

    The Chevelle 396 heater core is angled
     
    Super Bald Menace likes this.
  19. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

  20. hugger

    hugger Well-Known Member

    Yeah I use the 68-72 one,..they fit the 64-67 better imo
     

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