'74 455 -- swap pistons or heads

Discussion in 'Street/strip 400/430/455' started by NealWright, Sep 29, 2017.

  1. NealWright

    NealWright Active Member

    Stock '74 455

    I have about $2500 ... figure I can either

    1. Swap forged pistons ... overbore, mill deck, etc ... already have Molnar rods. Figure I can build a solid 10.5:1 bottom end, stock '74 heads, no rebuild

    OR

    2. Swap heads ... set of good TA Stg1 SE's ... stock '74 bottom end, just new seals

    I'm leaning toward Option1, then add heads down road ... I don't think any head/cam combo is gonna like my 8.1:1 compression.

    But, honestly don't know which would show biggest improvement
     
  2. cjeboyle

    cjeboyle Gold Level Contributor

    I am sure others will chime in but I say get the heads first. It is the single most significant upgrade you can do.
    Cliff
     
  3. sean Buick 76

    sean Buick 76 Buick Nut

    I say build the bottom end
     
  4. Stevem

    Stevem Well-Known Member

    Build the block strong first as you can then leave the short block in the car and swap heads down the road as trying to add possibly another 60 hp from 50K or more mile motor will in short order make for problems!
     
  5. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    The '74 heads are still closed chamber so not as bad as the '75 and '76 open chamber heads, the '74 heads should have 71cc chambers.

    Its always a great idea to start with a good foundation first, then add heads later. In the mean time perhaps you can do some basic home porting to make the stockers flow a bit more air until you can afford to top it off with a set of new heads.

    Throwing performance heads and cam on a 43 year old engine of unknown origin could be a recipe for a rod through the side of the block! GL
     
  6. Bluzilla

    Bluzilla a.k.a. "THE DOCTOR"

    You wouldn't build a new house on a weak or inadequate foundation, ..... in a situation such as yours I always recommend the bottom end first for all the aforementioned reasons.

    Larry
     
    300sbb_overkill likes this.
  7. Mark Demko

    Mark Demko Well-Known Member

    YEP!
    Years ago I had my heads rebuilt, put 'em on my 350, and BAM, rod knock!
     
  8. Stevem

    Stevem Well-Known Member

    If not rod knock then greatly increased oil usage , maybe to the point like I had ages ago where I did not even want to put my foot in it due to the embarrassment of the smoke trail that the motor would now leave behind me, lol!

    My 19 year old Brain gets its first big auto mechanics lesson the hard way, but now at 62 I may overthink things , but there's no oil smoke behind me!
     
  9. Bens99gtp

    Bens99gtp Well-Known Member

    This is a tough choice. How do you plan to use the motor. Race, street with some track time. Keep in mind if you deck the block to get your compression up, you might need extra machining on the heads you have now, and the new heads to get the port alinement correct. We just pot stage heads on our 464 that has only a clean up cut done to the deck we didn't need any extra machining to heads. Just a .040 head gasket and .060 intake gasket.

    I feel it worth the extra to buy pistons that fit the compression height needed to save the extra machine cost of lots of decking and head a linemen that sometimes come with off the shelf pistons that have 1.9xx compression height
     
    300sbb_overkill likes this.

Share This Page