'85 Ram 150 Emissions problems

A few questions: Emissions test came up exceeding HC levels. I changed the plugs, replaced some hoses that were cracked that went to the EVAP canister brought the idle up to snuff. I checked the timing, which appears to be dead on (but doen't really feel too good). 12 degrees bdc (I think) exactly about 7 out of every 8 sparks - then the 8th one nothing. The mark is nowhere to be seen. I have a pretty cheap timing light, is that it or is it misfiring or something? You can feel it idling kind of rough. Also, I cannot find an O2 sensor to save my life. There is nothing where the Haynes manual says it should be. Is this engine pre-O2 sensors or am I not looking in the right spot. The manual shows it just under the spark plugs on the driver side. I looked every where else I could climb as well. The EGR valve and PCV appear to be fine and it failed again. Better, but still failed. I'm fairly new to working on this vehicle. The extent of my knowledge comes from keeping a '74 beetle running nice and good. Any help I would greatly appreciate. Thanks. Todd Wilson