I assume my carb has been modified since the jets were changed an the afr plug was pulled...it's running well since I replaced the choke cable. I still get an occasional pop but only while warming up. once it's warm no popping. there's so many opinions on the slide/spring. Some guys say don't drill the hole larger, some say make it slightly larger but not as big as CV performance says to. some say avoid the aftermarket springs, some say cut a coil off the stock spring. adjusting the needle is another way to raise/lower the afr. hopefully someone will chime in on that slide drilling/spring question on what has worked best for them that's try multiple combos.