What are the plans for the car ?
Street use, I'd stick with your existing intake & carb.
Drag strip, maybe the friend's idea, but I'd test them both back to back.
I'm guessing that converter has probably around 2500 stall; might be a bit low for the old 284/484 cam @ 340-ish CI.
Way better cams than that on the market in the last 30 years, but may not be in your plans to change.
11.0:1 - was that measured ? That's a lot for pump gas with iron heads.