In answer to your question, no all 360 truck exhaust manifolds are not the same. Early manifolds did not have extra opening for the emission ports in the heads. If you use them on an emission head that still has the ports open, you will have 8 exhaust leaks. There are also manifolds out there with a flat extension under the exhaust port to cover the emission ports, the later emission manifolds have an extra section below the exhaust port for the emission port to dump into. Also, the right side manifold originally had a heat riser which the left side does not have. Too bad I don't have pictures to make all this visible. Gene