From what I've learned the Truck Avenger requires a lot of tuning to work properly on smaller cubic inch motors/stock motors. I've got a 670 CFM on my 305 (with only bolt on mods and a tiny bit of cam). I've ended up changing the accelerator pump to the 50 cc version and also changed the accelerator pump cam to allow more fuel to get in the carb from an idle (mine was bogging pritty good also).
With the back firing out fo the carb, I've first look at your timing/ignition first before looking firther. I know that when I installed the Truck Avenger for the first time it ran really really smooth @ idle (better than my old edelbrock ever did), it's when I start driving it that I noticed that these Holley carbs need lots of tuning to get them dialed in to your specific motor (even though Holley advertises out of the box performance).
With the back firing out fo the carb, I've first look at your timing/ignition first before looking firther. I know that when I installed the Truck Avenger for the first time it ran really really smooth @ idle (better than my old edelbrock ever did), it's when I start driving it that I noticed that these Holley carbs need lots of tuning to get them dialed in to your specific motor (even though Holley advertises out of the box performance).
