I understand both sides of this. One is that just buying a Pontiac to start with would save money and time. The other is that there are none down there and maybe doing the change over from a camaro would be fun, and could be done over time without the cash up front that another car might require.
It is your money and your car, do it your way. It can be done, but it will cost a lot more in the end than if you just wait for the right Pontiac to come along.
Either way you go it will be a cool project.