Jet me just say I agree with ExJunk, 2old2fast, and 409T. Now on the carb leveling the carb leveling thing, that intake manifold, by design, is designed to have the carb sitting level with the motor mounted in a stock car.
Ever notice that the competition manifolds are milled even with the centerline of the Crankshaft! If you got things where you want it and the exhaust doesn't follow the line of the body and the frame, set a protractor on there and line it up, see what the Angle is.
Take your exhausts off, off to a fab shop that has tubing bender, and right were the 4 head pipes fit inside the collector, heat it there slightly, and break it there. (Breaking as in beading it).
it'll take you longer to pull it off and put it back on than it will be to bend it where it's in line with the frame. Just a thought....