Just a heads up, probably old news for anybody who has done a 3g swap but, SRT8 manifolds from a Grand Cherokee are a bolt on fix without spending a king's ransom. That is what I am using on my 72 duster.
The exhaust manifolds I used for the HDK mock-up/testing are the Jeeps manifolds. They came with the motor and compared to the other factory manifolds, they hug the block extremely well....the only tight spot is where the steering shaft comes out of the fire wall which is not helped by the location I place the Hemi for optimum clearance EVERYWHERE....it is a dance.
my thought is....if I can get the bulky factory manifolds to clear / work.........aftermarket headers should be a breeze.