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Stroking a 3.5 with a 4.2 or 4.6 crank?

Discussion in 'It's A V8 Mate!!' started by hef19898, Jun 5, 2022.

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  1. hef19898

    hef19898 Well-Known Member

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    Hi folks,

    for some reason, I am investigating options to increase horse power of my 3.5. A new cam, Kent 200 (180?, I'd have to check), is sitting in my workshop, as is the roller timing chain. Next on the list would be ported cylinder heads. So far so good. I'd prefer to stick with the double Zenith carbs, I can litteraly rebuild them in the desert by now and a snorkel is very easy to fit.

    Now I am wondering, does a later (4.2 or 4.6) crank, with the right pistons and so on, fit a 3.5 block? The block is rock solid, so no machining on the block. And preferably a straight swop, the Buick 300 crank is hard to come by and needs too much machining. Plus, I prefer a crank I know that works over a dubious one that is 10+ years older...

    Greetings!
     
  2. norseman

    norseman Well-Known Member

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    I'm no expert, but I can tell you that fitting a 3.9 cam allegedly gives around 10% more power.
    Some cam mods. are more suitable for manuals then auto's.
    That's the best I can offer, sorry :(
     
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  3. Marshall8hp

    Marshall8hp Well-Known Member

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    What engine do you have? What compression ratio? There are things you can do that will give you a good power and torque increase without much outlay, if you are starting with the right base engine.
     
  4. hef19898

    hef19898 Well-Known Member

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    I have a pretty solid 3.5 on carbs with the 8.something compression ration. Things to be done are a new cam, new timing gear, new oil pump and maybe new, and ported, cylinder heads with a sports exhaust. All of which are done, with the exception of the ehads, as replacements for worn out parts.

    The reason I'm asking is that, yes, more power is better. And I don't want to rebore my engine. If a simple crank switch is a possibility I might consider it. If not, well I'm reasonably happy with the engine as is.

    The plan is to stick with carbs, simomy because I can rebuild and balance them myself, I'm a complete loss when it comes to electronic fuel injection. And I like the dual carbs airbox which makes it trivially easy to attach a snorkel to.

    Changes to the carbs, e.g. different needles, are completely fine so.
     
  5. norseman

    norseman Well-Known Member

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    Typo?
    Cam rather than crank o_O
     
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