I think a methodical approach is required to carb issues.
These are the main phases to think about on these carbs:-
• Normal/Main running
If you can establish which of these phases aren't working, it narrows down where you need to look.
• Does the car idle? If so, the idle circuit is okay.
• Does progression work? Open the throttles gently by a tiny amount. If the revs slowly increase and the engine is smooth with no stumbling and spitting, the progression circuit/holes are okay. Note: Both the idle hole (below the throttle plate) and the progression holes (above the throttle plate) are fed by the idle jet.
• Does the acceleration circuit/pump work? Open the throttle wide quickly. Do the revs rise quickly and smoothly. If not, there may be an issue with the accelerator pumps, jets or nozzles.
• Does the main jet/venturi circuit work? Bring the revs up above 3000 RPM and hold steady. Gently and slowly increase to 3500 RPM and hold steady. If the engine runs clean and smooth when held steady above 3000 RPM, the main circuit is okay.
It sound to me like you have an acceleration issue. The huge increase of air delivered to the engine when the throttle is suddenly opened has to be matched by fuel from the acceleration circuit. May be worth removing the air cleaner and bends from on top of the carbs and checking for delivery from the accelerator nozzles when the throttle is opened. The squirt of fuel towards the open side of the throttle plates should be quite obvious.
I can't remember if the DRLA has a diaphragm or piston accelerator pump. Worth checking the linkages to make sure the pumps are being operated.