Dual quads versus big hammer!!!...

just an opinion. The secondary air doors are opening too quickly need to slow them down, keep tightening until stumble goes away . You could keep throwing larger squirters at it when the originals were probably ok.The original jets were probably close . The plugs look and probably are too cold as 318 said , thats why there not clean and hard to read .
I can disconnect the secondaries completely and it still happens...