power dies at mid-range... please help!

what carb is on it????? could be running out of fuel my car was doing it about mid track last yr. and went to check things over and carb was running out of fuel.....i had a dp on it though....mike
Edelbrock 600cfm, I cut fuel pressure back to 5.5lbs because prior to that the carb was flowing gas into the intake after shut-off (even when cold) from too much pressure... is 5.5 lbs not enough maybe?