Regulations on modified engines - Need help

[AUIIISR]

I NEED HELP!!!

Im looking for the legislations or restictions that tell me how I can calculate the max size engine that can be fitted to a car.

I no there some kind of formula thats used when Turbos and S/C are involved relating to the engine size and car weight, was just wonderin if anyone knows where i can find this on the net or if they have if handy for me to copy and read up on