I recently installed a new 350 in my 72 k20, and i am having problems with dieseling/run-on. The timing is set for 8 BTDC, and I just put new bosch platinum 4+ spark plugs. The compression is a moderate 9.1 to 1, and i normally run regular 87 octane fuel. Does anyone have any suggestions on whether i should retard the timing, or increase to more advance? Or any other suggestions to fix this problem? Im only 17 but and still learning, so i will appreciate your help.