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Fuel coming out of your exhaust sounds like your carb need some attention. Also, the idle could be a timing issue. Cheap wires on a non performance 305 shouldn’t make that much difference.
My 78 has a 86 305 with hei ignition. It has fuel coming out the exhaust, wet plugs and a yellow spark.
I agree on the carb being an issue and have a carb kit on it's way. But the yellow spark has me wondering if it should be white/blue or not? For what it's worth the arc will jump 3/8"