I had the same slight delay/hesitation also when flooring it, been messing with carb jetting, pump shot etc and have seen improvements on acceleration especially on the top end, but the slight delay was still there. Turned to timing, was at 18° initial, with 16° mechanical, used a vacuum gauge to increase initial to get the highest vacuum, backed it off slightly. Readjusted the idle screws and idle speed.. Now at 22° initial, reset the FBO plate to 10° mechanical. Better idle vacuum, still pulls strong, and no slight delay any more. Throttle plates were open too much into the transfer slots. Might be worth checking all that to eliminate the possibility?
