[68c10airstream]

Hi, typically if fuel goes into a hot exhaust unburned it will backfire loudly. I would assume that your having a lack of fuel. Inline fuel filter in the 2bbl or a plugging sock in the tank on the end of the pickup tube at the bottom of the sender. Easy to check the sock and check on fuel for debris by looking into tank with out sender. Slide your seat all the way forward, release the sender lock ring, disconnect lines and remove it. Now you can look inside tank. Remember no incandesent trouble lights around fuel, hot bulb cold fuel, broken bulb and then a garage fire. I know of many but not me. Every dealership i worked at i was the only mechanis initially with flourescent trouble lights. Good luck, Brian F