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Thread: Compression ratio on a 383 w/ iron heads?
          
   
   

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  1. 02-21-2006 08:18 PM #1
    70_"SuperNOVA"'s Avatar
    70_"SuperNOVA"
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    Compression ratio on a 383 w/ iron heads?

     



    I am currently building a 383 street/strip engine that will be going into my 70 nova. It is a new block with eagle forged crank, rods, and forged pistons. I will be putting in a hydraulic roller cam with about a 222/230 dur. @ .050 lift, with a .509/.528" lift. Intake is an Edelbroke Performer RPM airgap, with a Speed Demon 750. The only limiting factor is that i will be using the current heads off my current 350 which are World Products Sportsman II cast iron heads (2.02/1.60 200cc intakes 64cc chambers) My question is what comp ratio would be best for the street. AFR aluminum heads are awesome but at almost $1500.00 a set, its a bit pricey. I was guessin on around 9.5:1 to maybe 10:1. Any other tricks for a bit more power? Also what HP/TQ can i expect out of this combo? Any input is greatly appreciated. Thanks!!!
    !Supernova!
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  3. 02-21-2006 10:13 PM #2
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    9.5 to 10.0 will work well with that cam. Adjust the squish to 0.035" to 0.040" to prevent detonation.
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  4. 02-22-2006 03:24 AM #3
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    Re: Compression ratio on a 383 w/ iron heads?

     



    Originally posted by 70_"SuperNOVA"
    I am currently building a 383 street/strip engine that will be going into my 70 nova. It is a new block with eagle forged crank, rods, and forged pistons. I will be putting in a hydraulic roller cam with about a 222/230 dur. @ .050 lift, with a .509/.528" lift. Intake is an Edelbroke Performer RPM airgap, with a Speed Demon 750. The only limiting factor is that i will be using the current heads off my current 350 which are World Products Sportsman II cast iron heads (2.02/1.60 200cc intakes 64cc chambers) My question is what comp ratio would be best for the street. AFR aluminum heads are awesome but at almost $1500.00 a set, its a bit pricey. I was guessin on around 9.5:1 to maybe 10:1. Any other tricks for a bit more power? Also what HP/TQ can i expect out of this combo? Any input is greatly appreciated. Thanks!!!
    The 200 cc heads you have now will support over 500 hp.Why change?
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  5. 02-22-2006 05:58 AM #4
    rumrumm's Avatar
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    Are you using dish pistons? Because flat tops will give you over 11:1 compression, and with that cam you will not be able to run on pump gas. Even if you are running dished pistons, figure out your DCR. You don't want to be more than 8.0 with iron heads. There is a DCR calculator on the Keith Black website.


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  6. 02-22-2006 03:02 PM #5
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    http://kb-silvolite.com/calc.php?action=comp2
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  7. 02-22-2006 06:20 PM #6
    hambiskit
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    Thanks for the link Tech...
    Jim
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  8. 02-22-2006 06:31 PM #7
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    yeppers....
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  9. 02-25-2006 09:27 AM #8
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    yes, ill be runnin 18cc dish pistons. Thanks a bunch for the link and advice all!!!
    !Supernova!
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