fuel and confused

I have a 70 duster 340 with a 451 stroker in it. When I got it running, it was amazing. But it seems the longer I ran it the rougher running it got. Im running a edelbrock 800 with a carter race mech pump. At first I thought it was the MSD box but After I opened the carb to make sure that all was well it was very dirty. So the carb is now rebuilt and from what I now understand edl carbs dont like anything over 6.5 psi. So should I switch to a more stock mech pump or should I switch to a holley carb with the race pump or a electric pump with a regulator. I realize there are a number of ways to go,so Im looking the combo my car needs for performance and relialibity. Or am I just freeking out and my fuel system is fine.:headbang: Im so close

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