1972 318 street build

how can you tell that they are for a magnum? and i dont really have the funds for the 400hp 318 lol i wish i could, i am also worried about to much torque in my dart as it is a unibody , so i guess thats another question how much torque is it gonna hold up to before it twists the body too much?
Don't worry. The car will take much more than a 318 can put out. I suggest you poke around here and read threads before you start building. Knowledge is power.