[Brad_bb]

I take it you guys are talking about static compression ratio. Have you read what Jim Hand wrote about dynamic compression ratio? He talks about cylinder pressure or rather dynamic compression, which is defined in large measure by the can and timing of the closing of the intake valve. Static CR assumes that the intake valve is closed at BDC so that you get the full measure of compression of the total volume. But in reality, it's almost never the case because the intake valve is not closed until sometime after BDC, allowing less than the full volume possible. The timing of the closing of the valve affects the dynamic CR. I suggest reading it on the Pontiac Street Performance website. It shows that there are more variables than many think.

If we do use the static compression ratio, and assume that the optimum would be 9.25-9.5:1, we can easily calculate backwards to determine how much volume we need(cc's) to achieve this, and measure and modify accordingly. This is likely much easier to do than trying to find the dynamic CR with a particular cam and working to achieve that.

In my situation, I want to remain with the heads I have and therefore I am locked in to a specific chamber volume(heads have not been milled to my knowledge, but I'll be checking their volume). I'm also locking myself into the stock tripower setup, which I'm sure is somewhat limiting for performance. Therefore it seems that there are only 2 variables left, cam selection, and removing material from the pistons. What are the advantages or disadvantages of dishing the piston as in an actual concave shape vs. milling the top flat off the piston? It would seem to be more difficult to machine and be certain of how many cc's you're removing.