With a Victor Jr., you will have to run a taperd (open) adapter spacer. Like the moroso 65000, 4150 to 4500 adapter. That piece is 2.00" tall. Wilson Manifolds makes one that is only 1.50" tall. And, the WM is a much nicer piece.
Man look in the parts section. I just posted a 4500 to 4150 brand new spacer for $40, open plenum, 2". Also I have a wilson Manifolds plate nitrous system that is an adapter from 4500 to 4150, but has a 350 hp nitrous plate built into it . It's an adapter and nitrous system in one. Sell it for $500 shipped. has burst panels, top of the line stuff. PM me if you want either or if you have more questions. I've ran dominators and adapters for years.