Hi, I recently bought a 1966 C10 with a 327 and a four speed. It was running great for a few weeks, but one day it started to backfire out of the exhaust. It started out by just doing it twice and still running fine, but as I was driving it it got much worse to the point that it was blowing two foot flames and sounding like a shotgun. It also started to idle really poorly and lost all power, so it seemed to be running on less than 8 cylinders. I ended up having to tow it home. I'm trying to fix the issue and I started by replacing all the spark plugs. I figured that it may have jumped timing so I checked it, but it seemed to be pretty close to spec, but it's difficult to check because of the rough idle. Does anyone have an idea of what I should do to fix it? At this point I'm thinking it might be the carb but I want to be sure before I spend a bunch of money on a new one. It has a Holley 450cfm economaster. Thanks for the advice!