Yes, BA Falcons are heavy but they will still cut a mid 15 second quarter mile two up which is quite quick for a family sedan. Anyway, I was just using that as an example. Also, keep in mind how understressed the LS2's are.

I suggested the atmo CA for budget reasons. Obviously you could upgrade to the turbo motor later if funds permit. The mods to fit the atmo CA aren't insurmountable nor expensive and the actual cost of the motor and gearbox will be much cheaper than what you could build an A series that would produce similar power levels for. In addition to this the CA will be a nicer thing to drive due to the extra cubes and factory nature.

Anyway, it's all food for thought. But if the reason why you want to fit a new motor is to beat 8's and WRXs then you will need more than 120rwhp.
Regards Matty

p.s. Dats-hot - excellent advice mate.