Back when I started in the "business", I pumped gas for a guy that worked on and sold Mopars - '35 Plymoth, '57 Savoy, '52 Desoto, etc. One day they had a 331 Hemi in an old Desoto that wouldn't start - gap the points, move the timming, etc., etc., Shoot the carb with either. Just as I walked past the front of the car someone keyed the ignition and POW, a backfire and a ball of flame came rolling out from under the hood. You didn't need to look far for me - I was under the workbench waiting for a "safe" time to come out.