You may want to check your valve springs,also make sure your mag pickup wires are separated from the coil orange and black leads.also check the polarity on the mag pickup.to do this look at where your timing is set,unplug the dist and take two short wires.plug one end into the dist and cross the wires before plugging them into the wire loom.start the engine and see if the timing advanced or retarded.the correct position is the retarded one.Bill