I know I have a dinosaur. It's a 1981 F-150 with a 351 Windsor engine and a 2V carb. Lately it has started backfiring on me when I turn off the ignition. What is up with that?

 

Timing is off. Set the timing at 8 degrees BTDC. Also check the carb and make sure no fuel is just dripping when it is at idle. Excessive fuel and a retarded ignition timing causes this. The timing chain has stretched over time and makes the distributor "off". Not a big deal.

 

Thank you. I adjusted the timing to 8 degrees BTDC and took the top off the carb and adjusted the float to 3" instead of 4" and she now runs fine. Thanks again.