Hi,
just a couple of question about increasing the compression ratio (CR).

There are some facts thats influences the CR:

1. Head design -->chamber volume
2. Pistons design
3. bore diameter
4. the type of head gasket (thickness)

If I port my head, I will increase the chamber volume and therefore decrease the CR. How much is that usually? Which effect is bigger?

An other possibility to increase the CR is to machine my cylinder heads. But I heard this might cause trouble with the intake mainfold. It might not fit tight? Is this correct?

Is it not better to machine the block? In my Chevy 350 cui is enough space at the top before the valves will hit the pistons. I have never read something about machine the block to get a smaller chamber and better CR.
What do you thing about that idea?

Regards

James