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Thread: 383 rotating assembly's

  1. #11
    Registered Member 55mike's Avatar
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    Quote Originally Posted by BamaNomad View Post
    Hmmm... 12cc pistons to ME means that there is a 12cc DOME on top of the piston (the OPPOSITE of a dished piston)... or am I missing something here?
    Good question, and perhaps I didn't say it correctly... I mean 12cc dish, not dome..

  2. #12
    Registered Member BamaNomad's Avatar
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    There may have been a change/modification in terminology since the days long ago when I spent more time on engine configurations; mostly these days I lean towards running 'factory stock' (but hopefully high performance) engines on the street. I never heard the term 'dish pistons' until the factory began to reduce compression and kill performance (mid-late 70s). Dish pistons were used to increase compressed volume and reduce compression in those motors.

    I just searched for and found a fairly good article (by Wiseco - a piston mfg) which explains significant detail related to piston crown design.

    https://www.hotrod.com/articles/insi...ons-explained/

    Obviously the piston crown design is complicated and varies by what type of engine and induction is planned. He makes a statement, which should be obvious, that most desirable is a 'flat top' piston, because the maximum combustion force is directly applied to downward motion of the piston. You have to think about head combustion chamber shape/volume, quench, head gasket thickness, etc when choosing your pistons (or let the engine builder choose it for you based on your objectives).

  3. #13
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    +12 cc = dome, -12cc =dish not that complicated to me. We put a dish 383 in a 89 TPI IROC with vortec heads. Ran 13.0 and still knocked down 20 plus mpg on highway. I believe FE Fords had dish pistons in the 60s. Diesel's before that.

  4. #14
    Registered Member BamaNomad's Avatar
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    that's the definitions I've always used as well, Mark... A 'dish' piston ADD volume to the combustion chamber, whereas a domed piston reduces the combustion chamber volume.

    What was bothering me was Mike55 stated intention to use 12cc dish pistons and getting a CR close to 10.5... I thought the CR would be much less than that (but I was thinking of a 350 ci engine.. Mike55 was referencing a 383.. so I went into my Compression Calculator and increased the stroke to 3.75 and the bore to 4.030 to get the 383 cid, and sure enough a (-)12 cc DISH piston with 64 cc heads, 0.020 deck height, 0.016 gasket (steel shim) will result in a chamber volume of 5.10 in**3 and a static CR of around 10.4...

    So Mike please excuse my confusion, as I have never built a 383 and wasn't thinking about the additional 1/4" stroke and it's effects.. I think the use of DISH pistons in such an engine very likely is one of the reasons that those engines are so powerful!

    PS. I've got a std 350 block (with bad forged crank) in my basement.... maybe I should consider buying such a 383 stroker kit for it..

  5. #15
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    Quote Originally Posted by BamaNomad View Post
    that's the definitions I've always used as well, Mark... A 'dish' piston ADD volume to the combustion chamber, whereas a domed piston reduces the combustion chamber volume.

    What was bothering me was Mike55 stated intention to use 12cc dish pistons and getting a CR close to 10.5... I thought the CR would be much less than that (but I was thinking of a 350 ci engine.. Mike55 was referencing a 383.. so I went into my Compression Calculator and increased the stroke to 3.75 and the bore to 4.030 to get the 383 cid, and sure enough a (-)12 cc DISH piston with 64 cc heads, 0.020 deck height, 0.016 gasket (steel shim) will result in a chamber volume of 5.10 in**3 and a static CR of around 10.4...

    So Mike please excuse my confusion, as I have never built a 383 and wasn't thinking about the additional 1/4" stroke and it's effects.. I think the use of DISH pistons in such an engine very likely is one of the reasons that those engines are so powerful!

    PS. I've got a std 350 block (with bad forged crank) in my basement.... maybe I should consider buying such a 383 stroker kit for it..
    ar

    No problem, I have damn near come to blows with friends who are mechanics with 40 plus years on the job who either think a 64 cc head on a flat top 283 is 10-1 or a flat top 454 is 10-1

  6. #16
    Registered Member 55mike's Avatar
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    So.... now that are all singing from the same hymnal, has anyone used the CompCams XE274 in their 383?

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    Ive used Comps 292, but would not put a flat tappet cam in
    any rebuild, unless it was completely stock.
    The 292 I used was yrs ago and it bent pushrods. Have two
    383s now with roller cams.

  8. #18
    Registered Member 55mike's Avatar
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    Quote Originally Posted by rdobbs View Post
    Ive used Comps 292, but would not put a flat tappet cam in
    any rebuild, unless it was completely stock.
    The 292 I used was yrs ago and it bent pushrods. Have two
    383s now with roller cams.
    No doubt a roller cam is the way to go. FWIW, I've been running a 292 Magnum flat tappet in my old 355 (AFR 190 heads, flat tops, etc...), with no issues. Future engine will be a bit tamer with the XE 274 in a 383. Guess it' s the old man in me............

  9. #19
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    Solid lifters are cool.

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