I hope that the Mods take no offence to this. Google 'Aircraft Engine Historical Society' to find out more re engines.
Thread drift, the company that I worked for in the 1950`s had Super Connies. They did an engine run on #2 one night, flames were coming out of the intake and exhaust at idle power and take off power, but it seemed normal around 2000 rpm. Engine shut down and ignition timing checked, ran again with same result, this was tried many times. Eventually it was found that the fuel injection pump had two master splines instead of one, it was fitted 180 degrees out of sync.