My 1975 Maverick has a 89 5.0. Cylinder 4 is dead (rear cylinder passenger side). "Sorry it's not a Mustang but you guys should know more about this than anyone else." It is Not firing and blowing lots of gas out of the exhaust. It has a street avenger carb, weiand intake, MSD 6al, msd coil, msd wires, msd cap and rotor and stock distributor. It has spark at the cylinder. I even swapped out the MSD box, cap and rotor, plug wires and got new plugs(same problem). Took off carb, cleaned and reinstalled(still same problem). Tried a friends edelbrock carb(same problem). Compression tested all cylinders and all are good. Checked valves and they are opening as they should. Looked in cylinder with camera and it still looks new. Roller rockers rock as they should. I am at a loss. I am thinking either the Distributor (even though it has spark possibly just not firing at the correct time), or could it be a intake manifold or head gasket leak. Any help would be greatly appreciated. I have been trying to figure this out since September. Thanks