Well, i've seen a few books saying the timing for a 1983 305 should be 6degrees. at 500rpm. I'm going to try your suggestion first 327 Jet. Hopefully it'll work well! I'm getting really irritated with this thing. All of a sudden after swapping the intake manifold (performer EPS) it is just all screwed up and runs smooth for 15 seconds, then backfires through the carb. UGH!

I wish i knew someone who was good with chevy engines/carbs!