680 would be sweet ryan,, as for my dart i go to atco rentals good air about 85degs the day i did 10.92s the next yr i did 10.80 with a heads done,still had more in it,,,when i put my buds proform 950 i lost all hook in the et radials tried 5 launches,,,so it liked the bigger carb for sure.. o yea 1 5/8 step headers through 3" x pipe and dynomax mufflers!