Disc Brake Hold Off & Prop Valves

Good evening AJ,
Just a little about the car. It's a 67 barracuda notch back, I owned this car for 35 years. So, it's has a 71" 340 w/kieth black pistons, 508 292 with tti headers. Iron heads ported/polished. Manual breaks/steering, hydraulic lifters with roller rockers. QF dp 750 black diamond, no VS. Full MSD ignition. Set at 32 degrees advance @2000 rpm. Full tub w/cage, 4 wheel disc break. It's a complete street car. Ok with that said I'm having issues with it running rich. This carb is kicking my butt. Do you think the carb is to much for that engine, should I consider a 680. I have adjusted the transfer slot, bigger Air Bleeds and power valve. It's a 4.5 was a 6