compression ratio help

changing blowers and need to lower compression
my computech calculator just quit
this is what i know
brad 5 head
.100 tall brad block
bore 4.467
stroke4.250
poured volume=91cc total 2 diff cyls. came out the same
i calculated 12.99:1

can someone tell me cc of 4.467x .100 cyl head gasket
i can figure compression and shorter rod from that

also what compression do most run with psi screw
at 115%
and at 125%
thanks

 

http://www.csgnetwork.com/compcalc.html
10.4/11.6 @ that od I would go with 10.4

 

4.467 x 4.467 x 4.250 x .7854 x 8 = 533 ci.

91cc + (533 x 2.0483)/91cc = 12.997:1 cr

4.467 x 4.467 x 12.87 x .010" = 2.568 cc's per .010" increase in 4.467 bore.

If your target is 11:1 then you need approx 109.25 cc's.

If your target is 10.4:1 then you need approx 116.10 cc's.

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