I need guidance

I have a 69 Barracuda with a stock 318. I currently have 2 exhaust problems. First, I'm getting exhaust in the car. I'm assuming I have a leak at one of the manifolds. I can smell it worse when the windows are rolled down. Secondly, the lowest point of my car (scrapes bottom quite often on our lovely Oklahoma roads) is my crossover. I ran over something many years ago that put a hole in the original and replaced it with one that didn't fit because I was in a pinch.

I'm looking for recommendations of improvements to make while fixing these two problems. I have been told headers wouldn't be very helpful for the hassle they bring. Fixing/replacing the manifold and running 2 1/4 duals has been suggested. What do y'all think?