They were all single exhaust. They did not have power enough to warrant duels.
The exhaust pipe made its way from the manifold to the rear of the car inside the right (passenger) frame rails over the axle and connected to a round muffler with a short turn down as a tail pipe.
Right out the repair manual for 64. I'm sure the 63 V8 was the same.

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"Tell it like it is or don't tell it at all" 1964 Falcon 2dr HT, 347V8 4V, dual exhaust, 5sp, pwr assist R&P steering, AM radio, heater with defrost and 2sp fan, electric windshield wipers, cigar lighter, dlx light group, bucket seats, console and full carpet.