CarbKing....WOW!!! I came to this thread looking for a clue on how to adjust the Rochester "2 Jet" on the '56 3/4T I just bought, and instead, I get the reason behind the goofy things my 500 cfm Holley has been doing since I set the idle mixtures with a vacume gauge. What you said makes perfect sense and is EXACTLY what my carb/engine have been doing. The Holley is on my 1964 GMC 1002 w/305E. Mine just cuts out and when I hit the accelerator it fires back up. In lower altitudes, when it fires back up, it would give a HUGE backfire!!
