Holley 1920 need help

starting in 1968 ALL engines was fitted with a lean idle circuit. the holley 1920 was one . the idle circuit can be fixed. BUT is VERY hard to do. my friend had one on 1969 dodge van. it would not idle. long story short. i fixed the idle jet. when done it would run so good we got it to idle at 250 rpm, so smooth you could count the fan blades.