I went with Sanderson Header DD8s (
About Sanderson Headers) on my 66 Barracuda with a 273, they are block huggers. I am very happy with them and they are now on my 408. TTI also has block huggers that have a little larger tubes - these would not work for my application without modification. And Sanderson is somewhat local to me
Both options give you better flow and reduce some weight from the car, stock manifolds are about 50 pounds and the sanderson's are 18 pounds
Good luck and let the fish roar