Dual Diaphragm Distributor

Short answer: 1968 was the only year for a dual-diaphragm (advance/retard) distributor, which retarded timing under certain conditions for emissions. Owners complained of a slight backfire while coasting downhill or decelerating, and a service bulletin had dealers disconnect the retard side. Yours likely already has it disconnected — check for a separate vacuum nipple on the advance/retard unit and make sure that vacuum source is plugged.

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[pdfjs-viewer url=/dtb/docs/68-I-45.pdf viewer_height=800px fullscreen=true download=false print=true]

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