The 1850/4160 has a driver's side fuel inlet, otherwise it'd be fairly easy to mimic the factory look. The only transfer-tube carbs that come to mind with a passenger-side inlet are the 4165/4175 spread-bores (Q-Jet replacement, bowl #134-110). Their inlet is on the center of the bowl, but it faces the passenger side to use an existing Rochester fuel line. It's even deeper than a center-hung bowl, though.
One other consideration when using an 1850-style bowl is that not all of them use an adjustable needle & seat. Make sure the one you're getting does! This is a mistake I could see myself making--concentrating so hard on the inlet that I completely miss the fixed needle/seat assembly. The 134-101 (dichromate) and 134-101S (shiny) both appear to have it if you're buying new.
I addressed doing something similar in posts 39 and 44. I'd prefer to find something a little less obvious than a big brass plug hanging out, though. I was thinking along the lines of threading for a socket-head set screw, then epoxying it in place permanently.
Another option--involving more work--would be to use 1850/4160 secondary bowls on all three. In addition to blocking the transfer tube provision, you'd need to modify for an external inlet. The 134-105/105S already uses an adjustable needle/seat per Holley. This option would provide for passenger-side fuel inlets. There's already a lot happening on the driver's side, so getting the fuel lines out of the way wouldn't hurt. I think it would also look better, but that's a subjective thing. The passenger side of the DC setup has a lot of empty space while the opposite side is rather busy.
