My information shows that the switch from driver side to pax side was made in 1971.
NB: There were actually three different front covers made for the LA. The 64-67 had the outlet on the drivers side and used a metal tab for the timing marks. The 68-70 same except timing marks were cast into cover. 71 and later the water pump outlet was on the passenger side.
If you use a 70 or earlier harmonic balancer with a 71 or later front cover, the timing marks are going to be 90ยบ off. Also, some harmonic balancers had symmetrical pulley bolt patterns, other did not.
The engine in the Demon is a 68 block with an 83 front cover et al on it. Because this kind of silliness goes on, suggest taking a good look at the front cover, harmonic balancer, and pulleys to be sure you get what you want if you are thinking of swapping things around on your engine.