Ok Got my Carb put on and the truck is running, I just have one problem

It seems my back barrels aren't open. I've pulled the throttle and the barrels open maybe a 8th of a inch. What am I doing wrong here. I'm guessing all my lines are run properly. My cjeck engine light turned off and I'm happy about that, I'm just not having any power when I punch it. Also it back fires at the carb when I punch it. Hope someone can help.... Thanks