400 or 455 opinions please

Discussion in 'Street/strip 400/430/455' started by jax gssxt8, Apr 19, 2017.

  1. jax gssxt8

    jax gssxt8 New Member

    I have a 68 gs400 conv 3 SPD Hurst,no ac PS or pb ( bought it new that way) I want to leave everything stock. but (a) install your recommended cam in the 400 or( b) install stock455 I have with your cam recommendation not looking for big horsepower all street no strip also dist has been recurved,carb tuned and gasket matched heads and slight bowl work. opinions please
     
  2. hugger

    hugger Well-Known Member

    For just cruising around the gain had from the 55cid isn't worth the work, ID just cam the 400 and have fun
     
  3. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    X2, I wouldn't bother swapping in a used engine when you could upgrade the BBB in the car already.

    Now if in your talking BUILD one engine or the other than that would most likely be a different opinion.


    Derek
     
  4. Schurkey

    Schurkey Silver Level contributor

    55 cid = 60+ ft/lbs of torque.

    I'd be all over that.
     
  5. Stevem

    Stevem Well-Known Member

    I must admit that your comment that you want to leave everything stock, yet are open to a motor cid swap is strange to me!
    The question here is how much life is left in the 400 in regards to how it's been maintained, and how many miles are on it?

    You mention a new Cam but you you can count on the motor right now being down some 15 HP if the stock timing chain is still in the motor and its loose which it likely is!

    Stuffing a new Cam ,lifters , chain and gears into a motor that if not needing new valve seals now can go south every fast when you hit them with more valve lift.
    All this being said, if you think due to age the 400 should get a rebuild and you have the 455 on hand already , then rebuild the 455 and swap it over!
     
  6. rmstg2

    rmstg2 Gold Level Contributor

    Yep


    Bob H.
     
  7. No Lift

    No Lift Platinum Level Contributor

    The OP mentions some kind of headwork. Does that mean the engine was redone lately? If so maybe a very slight cam upgrade would be good. Maybe a Stage 1 cam from TA. Nothing bigger for sure. By all means if it hasn't been rebuilt I'd install a fresh timing chain on there, cam swap or no. Also, if it doesn't have one already I'd make sure the oil pump has a Stage 1(white 60 psi) oil pressure relief spring in there just for some insurance. Stock pumps back then came with only a 40 psi spring.

    If it was my car the first thing I'd do is dump the 3 speed and install a 4 speed or even better go all out with a 5 speed. More fun around town and better out on the highway.
     

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