340 build No POWER need help w tune

Yes sometimes it does after acceleration " a quick snap"
Has very disappointing power at bottom end. Don't have the room to top end test yet.

The fuel pressure is ussually between 6-7 but the other day it was bouncing between 8-9.
I was under the impression that this pump does not require a regulator. And has its own cut off?? I am confident that the fuel pump is not my problem. When this carb was on my buddy's chevelle with a 400hp 400sb she ran very ritch for him.