No extra height, the car is lowered almost 2" in the front compared to stock. All of the modifications were to fit the wide 275's, with a narrower tire nothing would have been necessary. The width of the tires meant I had to trim the lip on the back of the front fender wheel opening, and I extended the fender to bumper brace to push the front corner out further. I also run tubular UCA's to clear the 9" wide front rim at full lock. But all of that was because of the tire width. Even with a 245 up front none of that would have been necessary.
The car is not tubbed, I have a 1/2" spring offset kit installed and about a 1/2" trimmed from the quarter lips, but the wheel tubs are stock. You don't have that much room on a dart though.
As long as you keep your front tire height at or below 26" not much is needed for modifications, it depends more on the tire width and backspacing below that.