How to calculate engine capacity after re-bore and decking??

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    Author Topic: How to calculate engine capacity after re-bore and decking??  (Read 1265 times)

    Offline OzCuda

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    How to calculate engine capacity after re-bore and decking??
    « on: November 29, 2006 - 04:14:16 PM »
    I have a '66 383 that has a 30 thou bore, standard stroke with '71 heads that would have been decked (even though they are list as the 88cc chamber, the guy that was building my engine said that he had measured volume and that compression would 10.?:1.

    So I'm guessing that this engine will now be over 400 cubes??? but how do I work it out or can someone tell me what it is going to be (just for bragging rights of course in a country that primarily ran small block V8s :thumbsup:).
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    Offline MEK-Dangerfield

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #1 on: November 29, 2006 - 04:51:11 PM »
    Let me say I have NO clue.  :pullinghair:

      Your heads have no factor here, as far as cubic inch displacement.. A 440 bored 30 over would be a 446. So you might have a 388?  :dunno: Having the heads ported helps horse power. 10:1 compression does too. Basically, I think you can brag more about your horse power than your displacement. Just my opinion.  :2cents:

      Mike
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    Mike

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    Offline Killer_Mopar

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #2 on: November 29, 2006 - 06:25:16 PM »
    Easiest way is to just use the calculator in the following link. You just need to put in your bore and stroke and the calculator will do the rest. You should be around 388-389...
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    Offline Oldschool

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #3 on: November 29, 2006 - 06:37:49 PM »
      Link?   :popcorn:   :popcorn:    :stirpot:    :bigsmile:   :cooldancing: 
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    Offline Four-Forty-fied

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #4 on: November 29, 2006 - 06:52:46 PM »
    Displacement = Pi x (0.5 x bore)^2 x stroke x number of cylinders

    3.1416 x (0.5 x 4.28”)^2 x 3.38” x 8 = 389.03 in^3

    (the ^2 means squared and ^3 is cubed. Area of a circle is Pi x radius squared)
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    Offline OzCuda

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #5 on: November 29, 2006 - 07:02:19 PM »
    Thanks guys - I was told it was going to be over 400 but this only further verifies that the guy I was dealing with for my engine had absolutly no idea whcih scares me with a half built engine.....
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    Offline Killer_Mopar

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #6 on: November 29, 2006 - 08:30:41 PM »
    Quote from: Oldschool on November 29, 2006 - 06:37:49 PM
      Link?   :popcorn:   :popcorn:    :stirpot:    :bigsmile:   :cooldancing: 


    Haha that might help....

    http://www.csgnetwork.com/cubicinchcalc.html

    If you scroll down and click on the automotive calculator link you will find all types of calculators for many different things.
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    Offline Chryco Psycho

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #7 on: November 30, 2006 - 02:45:50 AM »
    I agree , a .030 overbore will gain approx 5 CI
     decking has no effect on CI just compression ratio
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    Offline moper

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #8 on: December 01, 2006 - 11:59:41 AM »
    And I agree that's not who should be building that engine...lol. :bigsmile:
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    Offline Chryco Psycho

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #9 on: December 01, 2006 - 01:11:35 PM »
    Quote from: moper on December 01, 2006 - 11:59:41 AM
    And I agree that's not who should be building that engine...lol. :bigsmile:
    That too  :2thumbs:
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    Offline MJS73

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #10 on: December 01, 2006 - 03:24:01 PM »
    Quote
    I was told it was going to be over 400

    That would be a heck of an overbore.

    Mike
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    Offline Four-Forty-fied

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    Re: How to calculate engine capacity after re-bore and decking??
    « Reply #11 on: December 01, 2006 - 07:14:28 PM »
    Quote from: MJS73 on December 01, 2006 - 03:24:01 PM
    That would be a heck of an overbore.

    Yeah, .090
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