Help me understand the fuel system!

if that is a holley rotor style pump, like a blue or black, and you're running a factory sender and tank pickup, you may experience issues with fuel drainback, as well as priming the system initially. as someone noted above, those pumps are pushers, not pullers. it will absolutely NOT siphon gas up and out of the pickup tube, unless you take something like a shop vac and prime the fuel through the lines to it. those pumps are designed to gravity feed, not to siphon. also the regulator needs to be near the carb, and you need to get a return style, and run a return line. if you dead head the system, you'll get a summer or 2 out of a rotor vane style pump, before it gets hot from cavitation and dies. This is all from direct experience over the last 15 years of building street and race cars. i want to save you the issues that i didn't know about back when i started putting my car together, and this is definitely something i dealt with, and experienced all the issues above.