I've had an orginal Torker, Performer, Performer RPM, stock 289, stock 302, stock EFI and none had a cross over. Sounds almost like they used them during the early emissions years. Brought to you by the same people who lowered CR, increased quench distance, retarded ignition timing and valve timing, added EGR and air pumps... They were full of good ideas.
Yeah, I was muttering something similar about it probably being an emissions thing myself. Sounds like they were trying to crutch some other issue. If so, that would mean that someone thought it was a benefit, so I wouldn't write it off just because it stinks of emissions. (That statement sounds like someone just had beans for dinner ... )
If you think about it for a second or two you would realize that you are connecting two ports with the same pressure. there can't be any flow across that bridge but it can be a great spot to trap air because it is higher than the passages back to the front of the radiator. Any water in that cross-over is going to be stagnant. At least feeding it to the heater core allows it to go somewhere. The only cooling would come from heat radiating from the intake to the air and the surrounding metal.
maybe it wouldn't be a bad idea to feed the heater core from that rear passage... anything to promote circulation... for those that have the rear cross over.. i believe the 83-85 HO's had it.. but they needed all those ports for all the ****ty vacuum switches..