Slow RPM rate build during acceleration

Check the tach wire that plugs into the cap. If you have a dwell/tachomter gauge hook it up and get the readings at the distributor. If it bogs you may have bad secondaries on the carb! Also, check for vacuum leaks, get some gumout spray, and spray around on the vac lines, and the base of your carb, if the idle changes, you found a leak. Then on the back side of the carb is a vacuum hose at the base, unplug it and see if you have vacuum there, if it's weak or non existant, get a piece of wire coathanger and puh it in until vacuum increases! Carbon builds up in the base plate!