Fuel demand
I would think 3/8 line would feed it plenty of fuel??
1/2 from the tank to the pump and from the pump to the regulator. You can use 3/8 from the regulator to the carb.
Back in the day the fuel pump standard was some Mickey Mouse flow rate. I think it was 1 gallon in 30 seconds. That’s all good if you are standing still. Add motion and G force to it and it’s a piss poor way to judge a fuel system.
All pumps are rated at free flow. As the pressure goes up, the flow drops. A 110 gph pump is 110 gph free flow. Run the line pressure up to 7 psi and the RATED flow drops. I say the real flow is far less than what the graphs all say, because you have to add in hose lengths, fittings and such.
That goes for electric and mechanical pumps. Buying a pump based on free flow ratings or equally as bad, horsepower is a bad policy.
A 140 gph electric pump is about the minimum I run. And I do not dead head any pump, even if it’s a race car.