Hey guys new to the group. I have a 68 Dart 270 that I swapped a 318 into from a 74 satellite. What happened was I had my timing too far advanced and before I realized my mistake I had done a full rev up with it like that and it back fired hard through the carb spitting solid black pieces out of the carb. Since then I dialed in the timing properly but it has always ran since like it is missing a cylinder. The carb has been completely taken off and looked over...all is good. I have also pulled all wires off while running and it's not showing any specific signs as to one cylinder worse than the other. I just ran some seafoam really helped clean out some carbon build up and just pulled off the valve covers to start checking top end compents. At this point I am at a loss of where to go to be honest other than scoping out the the cylinders through the plug holes and pull the push rods out and seeing if one got bent. Any suggestions?? The only mods done to the 318 is Performer Intake, 600cfm holley, 360 heads from a 76 dart. The plugs are ngk r's(new) and i have a brand new set of wires, new ignition control module and ballast. Only old part left being the coil and distributor....now I do have a brand new distributor coming that is similar to the GM HEI coil on cap distributors to eliminate all electrical concerns.