This is brand new, never used. It has been drilled and injector bungs welded in to convert to EFI. I can make you the rails too if you want them for additional cost, but does not come with them. Its very easy to make rails so I decided to give the option to sell bare. This is 4500 plenum, rectangular port. The 454-R never came as an EFI option, so this one is ready for your build. I can also provide any EFI parts you may want or need also for additional costs.
Price for just the manifold is $275