600CFM Edelbrock #1406 on an '87 5.0.
When i get on the pedal, seems like there could be alot more power pushing out.
Running 6.5 fuel psi.
Where to start troubleshooting?

 

Make sure the secondaries are functioning, check float levels, accelerator pump..
Basically anything in the carb could cause this.

 

Check for vacumn leaks..........

 

600 CFM carb is a bit big for it. Unless you have a good cam in it. You may have a carb too large. Or a vacuum leak as was stated by Tinman. If you have a nasty cam in it try going a larger size or ask your local Speed Shop for more info.