1970 318 duster exhaust question???

Yea my car has the 8 3/4 rear with 3:23 gears, not that that would make me think it's a horsepower monster haha. I am leaning towards the 2in exhaust due to non performance aspect of this car. I know I have 2.5in on my roadrunner and that woke that up....but that car is a whole other monster.