Need to upgrade Fuel System

Okay a lot of you know I recently put a fairly mild 360 magnum in my 71 Dart. I got the timing and carb issues sorted out so then I moved on to traction issues. Last night while doing a "hole shot" I noticed 2nd gear didn't feal really strong and the engine started "surging" at about 4,000 RPM.

I immediately went home and had the wife watch my under hood fuel pressure guage as I revved the engine. At 3,500 RPM in park it is still holding 5 pounds of pressure. When I revved it to 5,000 she said pressure dropped to about 3 pounds.

When I put this engine in I thought I would have to upgrade to a 3/8 pickup and 3/8 line to a new mechanical fuel pump. I would say that is what I need to do now.

Only strange thing is it didn't do this when I first put the engine in. Maybe it's just the pump getting weak? I am currently using the mechanical pump that came in the car when I got it. Anybody have any good recomendations for a street/strip mechanical fuel pump? Is the Carter mechanical pump good?