Did you lube the pump cavity upon installation? Most don`t and this results in problems. Once I had a problem like yours, and I kept on chasing this problem for months, massive flooding problems. It turned out the vapour line from the fuel tank I plugged off, the tank couldn`t breathe so it was forming air pressure in the tank and forcing the fuel out of the only outlet it had, which was the fuel line going to the carb itself. One day I drove it and it seemed okay, I put $13.00 in gas in, got it in the next day to find it sitting on empty. After I shut it down the pressure build up caused it to force the fuel out of the boosters which filled the oil pan with about 3 gallons of gas. I was so ticked off at it I almost put a match to it.
However, set your fuel pressure at 4.5 psi. The test drive. You shouldn`t have any more issues. I don`t know what carb your using, but Edelbrocks and quadrajets don`t like anything over 5 psi. Some Holley`s and demons can use up to 9 psi, but all the ones I`ve used couldn`t use over 5.5 psi which is why I run it at 4.5 psi as I don`t like running it up to the borderline.
I don`t know about big block chevy`s, but small blocks don`t have a direct oil to the fuel pump, it simply gets oil that runs off the cam. Many install a new pump and don`t pack the cavity with lube which causes the pump to overheat which causes problems. If you didn`t lube your pump you may want to do so now. After you set the fuel pressure to 4.5 psi, check the float level and set it if needed.