The exact formulas you need can be found in Milliken and Milliken's "Race Car Vehicle Dynamics". It's expensive, but it's crammed full of usefull info, especially if you are doing a lot of re-engineering/redesigning. You can plug in all the info you have and not only can you calculate the bore diameter you want, you can also get a starting point for your bias bar offset.
You will also need to know front to rear weight transfer under braking, so you will need to know the CG height and the wheelbase.
What car are you building that only weighs 1500lbs?