Sounds like the plug wires might be out of order. Double check the plug wires to verify they conform to the firing order and the location on your specific distributor cap. Also, the distributor gear could have been clocked at the wrong azimuth when inserting the new distributor. You should be able to confirm top dead center for cyl no. one by removing the sparkplug and feeling for when the piston is at the top of the stroke with a screwdriver or slender rod, by rotating the crank pulley by hand. Here's a reference from the repair manual:
http://i721.photobucket.com/albums/ww217/lisadtcom/30Merc.jpg