Thread: Dynamic compression ?

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Hey guys, got a ? about a dynamic compression ratio. What i've got is a .030 350 sbc, sitting on the stand. It has a ballanced stock crank and rods, and .030 hyper flattop's from KB with 2 valve reliefs, and a 7.0 piston volume. The pistons a .010 in the hole, and im useing .028 head gaskets from GMPerformance. The cam that i chose is the XR270HR Retro-Fit Roller, with (495 in and 502 ex)(218 in and 224 ex @50)(110 lsa)(63 ABDC intake closing)(1600 to 5400 rpm range). The heads im useing are World Product S/R torquers, with 76cc chambers. The KB-silvolite calc, shows that i have a static c/r of 9.071, and a dynamic c/r of 7.366. The ? is, is the dynamic c/r of this combo in a good range, or should be adjusted, and if so what would be the best way to adjust it.(What is an ideal dynamic c/r in a street motor on pump gas) The motor will be in a 76 C10 shortbed sport truck, TH350, 3.42 gears. Please Advise

I don't use calculators....I do an actual pour of the engine....When mocking it up I pour, usually mineral spirits, the cylinder and count the cc's used....Then I use the equation in the back of a Lunati catalog to do it the rest of the way manually....

Your dynamic is fine....you cam change it easiest with a cam swap.....a 114 lsa will have a higher dynamic while a 106 lsa will have a lower dynamic....to a point .....but all the factors Denny mentioned DO affect the dynamic.....

All in all you should worry more about the static.....but remember just because KB tells you 9 to 1 doesn't mean anything unless you do all the measuring and math yourself.....

just goes to show you....people here really know how to help you.....

Tech...I agree....on both accounts