I believe the pickups were originally straight back from the metal heat shield that was under the bed above the muffler, which would be toward the driver side, but turning out [and down] is a good idea
"When we tug a single thing in nature, we find it attached to the rest of the world" ~ John Muir "When we tug a single thing on an old truck, we find it falls off" ~ me Some TF series details & TF heater pics