318\a904 swap in 65 barracuda

hi everyone, just curious what it takes to swap in an la318 and an a904 in a 65 barracuda, car car has a slant 6, I know it will need different motor mounts and I already had a driveshaft made for the car with a slip yoke. will probably need a new tunnel shift and a cables too right? for the trans? also are there any aftermarket early abody small block headers available? all advice will be appreciated thanks