Stock it's emission calibrated and would need some help to work well on your 455 build.
Remanufactured who knows? They can be OK to PATHETIC in quality control and often "butchered" up some with lead plugs driven into the bypass air passages, and even the threads drilled out for the N/S assembly and some POS double "O" ring deal pressed in there.
I try to avoid anything commercially remanufactured if I can help it.
I would not mess with used E-chokes. Every one I've installed has taken a dump so we quit putting them back in place several years ago to save customers a little money. The few times I did they crapped out within a months or so and we ended up having to replace them with new ones.......Cliff