Well .090 is a good start! you need to take a piston to deck height measurement (how far the piston is below the deck of the block) then using your head gasket specs (bore/thickness(Steel is .021 and felpro's are .037)) and combustion chamber volume(cc's) you can figure compression. if your running 91oct and a street cam you'll probably be in the 9.5:1 area but thats not for sure till you get the cam.
I run the same headers, i would be running a dual 2" exh or dual 2" into a single 2.5" for a basic street car. That rear will last for awhile if you keep your foor out of it, but a 8.25 would be awesome and has 4.5" pattern
DONT RUN THE COMP CAMS, they nitride harden the cams which is much harder than the oil pump gears. I.E. the oil pump gear fails and you lose the motor in almost all cases. Call OCG (oregon cam grinders) for a regrind, cheaper and better. What do you want the car to do? you say 225 hp but is what wheel or crank? do you want mpg or a weekend warrior?
need lots of info about where everything is NOW and what you plan to do
