I am running a Southern Automotive 427 center oiler with a cp 501 cam and 2X4 . The car runs around 100 c not much more but it is rich and fire burps out the side pipes if the car is hot just like yours. The carbs are to rich, putting un burned fuel into your pipes after the car is turned off, the pipes being hot fires it off. Many different reasons all centering on the carbs. Do the throttle blades close all the way at idle? Are the Power valves blown and dumping fuel into the engine? Are the secondaries sloppy and opening a little at idle/ Will the car idle? At what/ What carbs are you running? Is the timming right? Are the floats set right. You may want to look at my thread "Holleys to Rich" I am putting new holleys on this weekend. Times awasting winter is coming. I will rebuild when it is to cold to drive.
