Accelerator pedal laggy?

i bet half your issue is too many layers of carpet/insulation and the pedal just can't get enough travel.
although you said lack of power isn't an issue so have you jammed the pedal down with a lever or bit of timber then checked if you have actually got full throttle at the carb'? if it's getting full throttle now lifting the pedal higher will only end up breaking the throttle cable, unless you fit a stop of some kind under the pedal pad on the floor.
neil.