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Old 11-02-2008, 06:23 PM
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how much comp. should I reach for on 350?

Alright guys this will hopefully be the last post on this project, Gen 1, 2 bolt 350, Flat top piston 2 valve relief, not sure what cam yet with cast crank, and stock rods. question is what is the MOST compression i could run and still use 92 pump gas, or be right on border line. and what heads would get me there, 58cc,64cc,65cc,75cc etc.... or a list of what the compression would be would be great,... thanks guys

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Old 11-02-2008, 06:29 PM
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What pistons did you use?

I've got Speed Pro (Federal Mogul) H345NCP-40 flatop four valve relief, .004" from deck. .039" compressed headgaskets & Vortec 64cc heads.

If I remember correctly the estimated compression on mine is 10.2-1,and I've been using 91 octane without a problem
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Old 11-02-2008, 07:54 PM
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I've heard of 12 and even 13:1, but that was in a super expensive build with all of the tricks. For general hotrodding most stick with 11:1 or less- and even then you better have that thing built and tuned perfectly. since it appears you are not well versed in engine theory and dynamics I would recomend 10:1 or less.

Keep in mind for streetable power 10:1 can be a LOT better than 12:1.
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Old 11-03-2008, 01:21 AM
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That question is like asking "how hot a girl can I land tonight?" It depends on a few thousand factors including driving style, auto or manual, iron or aluminum, domes or flat tops, cam timing, thermostat temp, accuracy of the fuel tune, effectiveness of the ignition system, turbulence in the chamber, squish and quench... the list is nearly endless.

Master tuners using all the expensive mods can get a 12:1 engine to run on 87 octane, while a ham-fisted novice might not be able to get an 8.5:1 engine to run on 93.
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