c/r dilema
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Joined: Sep 2013
Posts: 37
From: Ontario
c/r dilema
hi all. thanks for the responses. i have the mill apart and am gonna oversize it. next step is to get some slugs. what is the best compression ratio to run? i enjoy putting down a bit of rubber. i believe the specs originally were 310 hp 4bbl carb 10.25:1 c/r. i dont want a dog to drive but i realize our fuel is a joke. i just want to find a balance of power and driveability. it is a stock 4spd ragtop with cast heads and quad. i know its a tough question but would love to hear everyones thoughts on this. thanks. paul
Last edited by wabasto; Mar 19, 2014 at 10:17 AM. Reason: additional info.
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Joined: Feb 2013
Posts: 15,411
From: Phoenix, AZ
That is nearly impossible to answer as there are many factors involved, such as:
- the fuel you plan to run (many places have 100+ octane racing fuel available, others have nothing better than 91)
- your camshaft timing parameters (long overlap/later intake closing = lower cylinder pressure so it allows higher compression; short overlap/early intake closing builds more cylinder pressure)
- type of heads (aluminum allows higher CR than iron)
So with all that said, 9.0-9.5 would be appropriate for most situations.
- the fuel you plan to run (many places have 100+ octane racing fuel available, others have nothing better than 91)
- your camshaft timing parameters (long overlap/later intake closing = lower cylinder pressure so it allows higher compression; short overlap/early intake closing builds more cylinder pressure)
- type of heads (aluminum allows higher CR than iron)
So with all that said, 9.0-9.5 would be appropriate for most situations.
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Joined: Jul 2009
Posts: 3,211
From: St Augustine
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