I've always respected the fact that Chrysler used 5/16" fuel lines on low output big block cars and 3/8" on Hemi's and high output big block Wedge cars.

I have a mildly modified 440 in my 66 Coronet 500 that puts out around 400 hp and I run a 3/8" pick-up tube and fuel line all the way up to the carb. For the fuel pump, I run one of the Mopar Performance hi-performance mechanical pumps.(part #P4007039AB) To keep the fuel clean, I have one of the Fram HP1 canister style fuel filters back by the stock reproduction fuel tank and a 3/8" in-line filter up front between the fuel pump and the Holley 750 cfm vacuum secondary carb. I've had zero problems with this set-up for many years.

Richard