Timing or carb ?

[Jabes1]

Sounds more timing related. Are you using a timing light to adjust your timing? Initial timing for HEIs should be around 15-18 degrees advanced. Warm your truck up, turn the idle mix screws all the way down, hook up a vacuum gauge and adjust them out a quarter turn at a time to achieve the highest vacuum. You want the screws adjusted the same. Idle mixture is just that....idle mixture. I'm thinking if you get the carb and timing adjusted correctly the bog will disappear. I seriously doubt you're under carb'd or lean with a 4bbl on that six.
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