Take a look at your float level, then set the valves. See if that helps.
What does the tail pipe look like? If it looks like it's coated with soot, you have a rich burn problem. If it's backfiring, you may have timing issues, but I would suspect your valve lash needs revisiting. Bouncing could be related to the loose timing set, but is more likely a loose spring perch in the distributor, or vacuum advance coming in from ported vacuum that is unstable. This can be effected adversely by valve lash issues.
A place to start. It's really hard to diagnose something that's not right in front of me.
CJ