Calculating Comp. ratio??

[green724x4]

I am currently dying to dust off my truck and take it out of storage. I have been planning doing a couple more preformance mods.
Other than adding a MSD ignition box with boost control, I am looking to increase my boost pressure, from a 6 lb pulley to at least an 8 lb. I have been running the calculations several times on many different web sites. I keep getting ultra low static compression ratio of only 7.0:1 or so.

Here are some numbers to crunch

431 cubic inch

4.28 bore
3.75 stroke
.040 head gasket
36.1 cc dome pistons
124cc combustion chamber

Trw 226 pistons
Open chamber oval port from 72' passenger
My guess was about 8.0:1 but after running the numbers looks like I have lots of room for more BOOST.
70rs/ss some feed back would be great.
thanks