First off, elminate the obvious. You have the plug wires in the right order on the distributor cap going to the correct plugs? Then did you buy the correct plugs (heat range, etc.)? Are they installed properly, (i.e. tightness and not crossthreaded)? Is the distributor cap on tight? If all of this is correct, then it's time for some in-depth troubleshooting. Let us know what happens.