Ok I measured the pump and its correct length of 5 5/8" long. Everything else lines up so I guess I guess this shinny billet pulley is another part to be added to the scrap heap.
NTFDAY, thanks for your input and for an education, I have a 283 with a 327 crank that uses a bolt to hold the balancer on .
I'll have to get some pics.
I see they make shims for the balancer but that means the power steering pump and alt. would also have to be shimmed out, not really an option .