Ditto - replace the needles and seats, also double check your float levels and consider dropping them just a little lower to see if that helps. If you've been getting backfiring, consider changing the power valves too. My hot starts are a lot better now that the carb is freshened up (I also installed a phenolic spacer to keep the heat down), I'm waiting for the heat of the summer to see if everything is good, but so far in the cool spring weather it's better than last year.
You can get a Holley rebuild kit fairly cheap, and after I saw one torn down and put back together in under 1/2 hour, it doesn't seen so intimidating.
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