Carb fuel pressure issues

So I have a 410 stroker and a Holley 750 dp, automatic trans with 4200 stall. I am having two issues. The first issue is that I adjust the carb to the fuel pressure it's set at. This means the bowls, front and back. Then in gear I adjust the idle mixture screws (4 corner). Take it for a drive and it's great. Next time out, it's breaking up when I press the throttle. Pull back into garage and it's dumping gas into carb, so I lower bowls until it stops. I keep doing this until bowl level is set so that when I turn the car off and shake the car, fuel comes out, with a hip check. Take it for a spin and the car wants to die when I come to a stop, I am guessing this is the idle mixture screws needing adjusting again, but the biggest issue that was scaring me was the engine breaking up..



The second issue is my fuel pressure. I have a carter Super Strip pump that flows 140gph at 8psi. The Holley regulator splits into two lines, one for each bowl. At cold start up I have 6 psi and then it gets to 8 where I want it. After driving it for a bit, the fuel pressure will vary from 6 to 8 and sometimes lower. Can you help me out with this? Do you guys think the pump is not handling the engine? Maybe the regulator is crap? And maybe this is causing my erratic bowl adjustments because of inconsistent change of fuel pressure?

The gauge is a Mechanical Autometer Gauge NEW!


Any help is greatly appreciated and I will do all steps asked to do, Thank You!