I think I may have found the source of my problem (have to crank up after running a few minutes to get fuel to carb).
So I have the 1406 eddie carb in my 72 cuda with a 318. I have a vacuum canister, but the carb fuel bowl line was never hooked up, because there was no place to hook it to in the carb. Take a look at the eddie pic below. It shows a fuel vapor bowl line near the fuel inlet, but ONLY for the 1400 model. So is that my problem, in that I need to hook that up, but can't with the 1406 model?