The specs being asked for are for an engine dyno to see what the baseline is for the motor.
Without a baseline you can't go anywhere.
As far as needing a cam that is for ported heads and matching it to what you want someday that is absurd!
If you put a 10 second cam in a stock motor the car would run 15's instead of 13's.
There are steps that you need to take. Most people don't have 20 grand to dump in a car today and build the car that they want. Those of us that don't have a ton of cash take steps like putting the largest cam that will flow through stock heads like mike183 said. Later there will be another cam that is given the car will never be fast enough
The car will be a daily driver. Driveability is a must, the GTO will be driven to the drags and raced every weekend.
This is what we are thinking:
Bosch +4 plugs
KN air system
Headers full exhaust
Mickey Thompson ET street radials
There will be more to come. The heads will not be ported. I will get this car to 12 flat without porting the heads !