1969 Z11 Exhaust manifold question

I have a 69 Z11 and am trying to figure out what are the proper exhaust manifolds for the car.  It has the original engine (350/300hp), original 4 speed trans, and original rearend, the car is also a  non A.I.R (smogger car).  The car has a few odd options such as the endura front bumper, shoulder belts, etc. Thanks, Dan from www.numbermatching.com