early exhaust manifolds fit 67-69 cars?

I have a 69 dart-- that has a 318-- Will the early style pre-67 exhaust manifolds fit? what is the difference between the early "a" manifolds & the 67-69 style -- if any? thanks-- I know the 340 style is a better unit & more $$ but this car is going to be a croozer-- doesn't need speed.
the car rolls right now so it will be a while before i get to this point. thanks Lawrence