compression ratio ?

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how do you figure compression ratio ? formula? i know what bore size is 4.375
stroke 3.75
deck 9.98
compression height 1.300
piston deck -.008
h/gskt .039
head cc 84 aluminum
flat top piston (wiseco)
engine is a 451 b engine with stealth heads

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Do the pistons have valve reliefs, if so do you know the CC of them. We need that to get a accurate ratio, we need the bore size of the head gasket also

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the pistons have reliefs ,total 10 cc ,the head gskt bore is 4.41

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the pistons have reliefs ,total 10 cc ,the head gskt bore is 4.41

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Unitred Machine(KB)on line calculator says 10.12 to 1 comp. ratio Good, safe pump gas combination

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the pistons have reliefs ,total 10 cc ,the head gskt bore is 4.41

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Unitred Machine(KB)on line calculator says 10.12 to 1 comp. ratio Good, safe pump gas combination

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Yep! Thats what I used, but @ 5cc 10.174

But a 5cc difference should be more then a .05 comp change. I,ll run the numbers again @ 10cc


EDIT, Yep, with 10cc Cab, I get 9.74 comp.

84cc head
5cc piston
4.375 bore
.008 deck
.039 gasket ht.
4.41 gasket diameter
3.75 stroke
= 10.174

add 5cc piston for a total of 10 cc = 9.74 comp @ United Machine KB.

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the pistons have reliefs ,total 10 cc ,the head gskt bore is 4.41

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I seriously doubt you have 10 cc valve reliefs in your flat top. Its more then likely 5 cc,s and your just doubleing it.

With that said and with a 5 cc figure along with your other info, around a 10 .174 or 10.2 comp.

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Could be 10 CC's.