compression formula

I think the rule of thumb is 12-15% per whole point of compression(like from 9:1 to 10:1). Its a percentage because the more power you make on low compression, the more you will make with high compression.

You'll have to get supporting parts, though. A stock 5.0 with 11:1 compression wont run on pump gas and will be badly choked by the induction.

It depends on the total setup. More compression will usually make more power. With higher compression, exaust will be pushed out harder, and intake will be pulled in harder, resulting in more air in the combustion chamber. The compression will heat the mixture and make it more effecient, a hotter flame, making more power. This heat can also result in detonation. This is only static compression. With the stock heads, intake, and exaust, there would be some gain, but not a lot, while with a good H/C/I/E setup, it will make a lot more. You want all the compression you can get without detonation. The prevent detonation, you need higher octane fuel, or a colder air charge (intercooler, methanol) to keep the heat down. Cam specs can also have play in this. Compression is just one page of a book that determines engine performance.

I forget how to figure that out, I only know the formula to find cubic inch displacement, compression ratio, and Liters.