You did not mention your ignition coil. If its not new, replace it. You should check the dwell, it should be 28 to 32, 30 preferred, and it should not fluctuate much if any under acceleration. Have your distributor guy pull the dist out, and put it on his machine and show you that it will get to lets say 7500 RPM without the points floating. If nothing is found in the ignition, check you valve adjustment, if its got solids.
Good luck, I hope we were able to help you out.
Wednesday, December 2nd, 2009 AT 10:55 PM