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what compression ratio?

Discussion in 'The Garage' started by chevystepside, Jul 14, 2003.

  1. chevystepside

    chevystepside 1/2 ton status

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    what is the highest compression ratio that a tbi 87 350cid engine be built to with no computer mods?
     
  2. zakk

    zakk 1/2 ton status

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    running what octane? after market heads? headers? stock cam?
     
  3. chevystepside

    chevystepside 1/2 ton status

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    regular pump gas or mid grade.stock 76cc tbi heads with malley budget performance valves. cam is going to be a dual energy 12-249-4 comp cam 206deg 212deg .434intake .444exhaust.
     
  4. Don

    Don 1/2 ton status

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    9.2 with cast iron head's
    9.7 with aluminum head's
     
  5. zakk

    zakk 1/2 ton status

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    is that cam TBI-approved? I'd say 9.5 with a WELL tunes engine and mid-grade, with 92 in it at any altitude.
     
  6. chevystepside

    chevystepside 1/2 ton status

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    jegs said that the cam is ok for tbi motors.coolthanks for the info. now to pick the pstons for the compressions between 9.0 to 1 or 9.5 to 1
     
  7. Don

    Don 1/2 ton status

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    The compression ratio will depend on the cam too. Overlap.
     
  8. chevystepside

    chevystepside 1/2 ton status

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    the cam is comp 12-249-4 dual energy 206deg 212deg 434int .444exh 112deg. i,m looking at keith black silvolite hypereutectic pistons with +6.25cc 4 valve reliefs. they say that with a 76cc chamber head that the compression will be 9.2 to 1. head gaskets are going to be felpro .o41"thick.
     

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