I believe he is working with a SBF and if I remember correctly, they only offer an intake manifold for a Holley 4150 carb. I have yet to see one that is cast for a 4500 series.

I could be wrong though. If I am, I'm gonna be upset that I spent the time to weld the 4500 to 4150 adaptor to my Victor Jr. so I could run my Dominator.