does anybody how much compression is raised by shaving the head .20 thousandths? The block was decked only 0.8 and i'm using cp's 9:7.

 

.20 or .020

 

.20 thousandths=.0002" but I don't think that is what you mean
.8 decked is almost an inch, so I don't think that is right either.
The zeros and decmal points mean everything when doing these calculations.
We would also need to know the bore, stroke and what thickness head gasket you are using.

 

the head was milled .25 thousanths and its a 81.5 bore with a stock headgasket.

 

No it was milled 25 thousandths OR .025"...not .25 thousandths. Big difference

 

If your motor was really 9.7-1, taking .025" off would raise the c/r to about 10.5-1