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Old Feb 7, 2010 | 12:34 PM
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compression ratio help

Alright fellas, I have a hypathetical question. What would the compression be on an certain fe that has C4AE-G heads, 360 flat top pistons (std), 390 rods, 390 crank, fel-pro head gasket?
 
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Old Feb 7, 2010 | 10:24 PM
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Using this:

RSR Static Compression Ratio Calculator

and:

4.05 bore
3.78 stroke
rod 6.49
compression height 1.76
deck 10.17
combustion chamber 73.2
gasket .041
and NOT figuring the dish and/or valve reliefs in the piston:

10.04

Info from FE Cylinder Head I.D. and Application Chart

Note the chart shows a C4AE ----f, not a g. No g shown. See here re the "G":

https://www.ford-trucks.com/forums/928279-c3ae-g.html



http://www.kb-silvolite.com/assets/0...te_catalog.pdf

http://www.summitracing.com/search/B...c&autoview=SKU

+/- depending on the actual measurements, as all those numbers have a range in production and actual use.

If you have exact numbers, the calculator will give you a better number.
 
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Old Feb 8, 2010 | 08:34 PM
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Ok, something's goofy with the calculator. I enter everything in and the final result is 1.35. Am I missing a step or what do I do with this number. If this is right, what does it mean?
 
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Old Feb 8, 2010 | 08:46 PM
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You probably put 10.17 in deck height, which is what I did the first time. What they want is the piston-to-deck number, which I think is .030 in this case. I shoulda warned ya...
 
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Old Feb 8, 2010 | 09:44 PM
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Ok, now that works better.
 
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