From past experience readings two stokes plugs, that would seem a bit lean.
What situation, or RPM did you stop the motor before pulling the plugs?
I agree, Holley DP's are pretty quik on the throttle,
and probably use a bit more fuel. I'm running a 650 on the 340 and the response is pretty good except when the temperature gets really hot. This isn't computerized fuel injection by any means so, tuning to the weather is needed to keep it running crisp. Just another part of the experience owning a muscle car.