When we bought our J2000 it already had an HEI ignition conversion installed on the AMC 360 V-8. However, it was a cheapie import version that was a complete pile. The mechanical advance was not working properly and we tried everything to fix it. Ultimately it had been assembled with the wrong parts. The advance mechanism would make contact with the underside of the rotor. This resulted in pathetic engine performance over 1,500 rpm.