afb 4131s surge at wide open throttle

took it out for a ride and it is still breaking up when secondaries start to open . It breaks up even more with the air cleaner on . so......... it breaks up with a 74 rear sec jet now even with the previous sec jet 92 . it's been at each extreme high and low ....... lean and rich condition and still breaks up. running out of things to try.
One thing good is it flies like a bat out of hell on the primaries though.
going to pull the vac advance hose off and try next..